diff --git a/phpstan.neon b/phpstan.neon
index 39ec473537f..429e9f6e8d5 100644
--- a/phpstan.neon
+++ b/phpstan.neon
@@ -218,6 +218,8 @@ parameters:
 
         - '#Register "Rector\\Php81\\Rector\\ClassMethod\\NewInInitializerRector" service to "php81\.php" config set#'
 
+        - '#Register "Rector\\Php80\\Rector\\NotIdentical\\MbStrContainsRector" service to "php80\.php" config set#'
+
         # closure detailed
         - '#Method Rector\\Config\\RectorConfig\:\:singleton\(\) has parameter \$concrete with no signature specified for Closure#'
 
diff --git a/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/fixture.php.inc b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/fixture.php.inc
new file mode 100644
index 00000000000..daef049f323
--- /dev/null
+++ b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/fixture.php.inc
@@ -0,0 +1,27 @@
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class Fixture
+{
+    public function run()
+    {
+        $isMatch = mb_strpos('abc', 'a') !== false;
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class Fixture
+{
+    public function run()
+    {
+        $isMatch = str_contains('abc', 'a');
+    }
+}
+
+?>
diff --git a/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/fixture_equal.php.inc b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/fixture_equal.php.inc
new file mode 100644
index 00000000000..044cda46f28
--- /dev/null
+++ b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/fixture_equal.php.inc
@@ -0,0 +1,27 @@
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class Fixture
+{
+    public function run()
+    {
+        $isMatch = mb_strpos('😊abc', 'a') != false;
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class Fixture
+{
+    public function run()
+    {
+        $isMatch = str_contains('😊abc', 'a');
+    }
+}
+
+?>
diff --git a/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/identical_mb_strpos.php.inc b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/identical_mb_strpos.php.inc
new file mode 100644
index 00000000000..583b2cb371d
--- /dev/null
+++ b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/identical_mb_strpos.php.inc
@@ -0,0 +1,27 @@
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class IdenticalStrpos
+{
+    public function run()
+    {
+        $isMatch = mb_strpos('abc😊', 'a') === false;
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class IdenticalStrpos
+{
+    public function run()
+    {
+        $isMatch = !str_contains('abc😊', 'a');
+    }
+}
+
+?>
diff --git a/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/not_equal_mb_strstr.php.inc b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/not_equal_mb_strstr.php.inc
new file mode 100644
index 00000000000..8e1ca6f4c53
--- /dev/null
+++ b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/not_equal_mb_strstr.php.inc
@@ -0,0 +1,27 @@
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class IdenticalStrstr
+{
+    public function run()
+    {
+        $isMatch = mb_strstr('abc', 'a') == false;
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class IdenticalStrstr
+{
+    public function run()
+    {
+        $isMatch = !str_contains('abc', 'a');
+    }
+}
+
+?>
diff --git a/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/not_strstr.php.inc b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/not_strstr.php.inc
new file mode 100644
index 00000000000..4e3499ebb67
--- /dev/null
+++ b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/not_strstr.php.inc
@@ -0,0 +1,27 @@
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class IdenticalStrstr
+{
+    public function run()
+    {
+        $isMatch = mb_strstr('abc', 'a') === false;
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class IdenticalStrstr
+{
+    public function run()
+    {
+        $isMatch = !str_contains('abc', 'a');
+    }
+}
+
+?>
diff --git a/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_equal_strpos.php.inc b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_equal_strpos.php.inc
new file mode 100644
index 00000000000..7a91da6a599
--- /dev/null
+++ b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_equal_strpos.php.inc
@@ -0,0 +1,25 @@
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class OffsetStrpos
+{
+    public function run()
+    {
+        $isMatch = mb_strpos('abc', 'a', 1) != false;
+    }
+}
+?>
+-----
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class OffsetStrpos
+{
+    public function run()
+    {
+        $isMatch = str_contains(mb_substr('abc', 1), 'a');
+    }
+}
+?>
diff --git a/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_expression_equal_strpos.php.inc b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_expression_equal_strpos.php.inc
new file mode 100644
index 00000000000..b57186ea9d6
--- /dev/null
+++ b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_expression_equal_strpos.php.inc
@@ -0,0 +1,27 @@
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class OffsetExpressionStrpos
+{
+    public function run()
+    {
+        $offset = 1;
+        $isMatch = mb_strpos('abc', 'a', $offset + 1) != false;
+    }
+}
+?>
+-----
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class OffsetExpressionStrpos
+{
+    public function run()
+    {
+        $offset = 1;
+        $isMatch = str_contains(mb_substr('abc', $offset + 1), 'a');
+    }
+}
+?>
diff --git a/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_expression_mb_strpos.php.inc b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_expression_mb_strpos.php.inc
new file mode 100644
index 00000000000..5202f15e2d8
--- /dev/null
+++ b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_expression_mb_strpos.php.inc
@@ -0,0 +1,27 @@
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class OffsetExpressionStrpos
+{
+    public function run()
+    {
+        $offset = 1;
+        $isMatch = mb_strpos('abc', 'a', $offset + 1) !== false;
+    }
+}
+?>
+-----
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class OffsetExpressionStrpos
+{
+    public function run()
+    {
+        $offset = 1;
+        $isMatch = str_contains(mb_substr('abc', $offset + 1), 'a');
+    }
+}
+?>
diff --git a/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_negative_equal_strpos.php.inc b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_negative_equal_strpos.php.inc
new file mode 100644
index 00000000000..22c0564cbd9
--- /dev/null
+++ b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_negative_equal_strpos.php.inc
@@ -0,0 +1,25 @@
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class OffsetNegativeStrpos
+{
+    public function run()
+    {
+        $isMatch = mb_strpos('abc', 'a', -1) != false;
+    }
+}
+?>
+-----
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class OffsetNegativeStrpos
+{
+    public function run()
+    {
+        $isMatch = str_contains(mb_substr('abc', -1), 'a');
+    }
+}
+?>
diff --git a/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_negative_strpos.php.inc b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_negative_strpos.php.inc
new file mode 100644
index 00000000000..5f928270ad7
--- /dev/null
+++ b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_negative_strpos.php.inc
@@ -0,0 +1,25 @@
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class OffsetNegativeStrpos
+{
+    public function run()
+    {
+        $isMatch = mb_strpos('abc', 'a', -1) !== false;
+    }
+}
+?>
+-----
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class OffsetNegativeStrpos
+{
+    public function run()
+    {
+        $isMatch = str_contains(mb_substr('abc', -1), 'a');
+    }
+}
+?>
diff --git a/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_strpos.php.inc b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_strpos.php.inc
new file mode 100644
index 00000000000..6f2aadf4607
--- /dev/null
+++ b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_strpos.php.inc
@@ -0,0 +1,25 @@
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class OffsetStrpos
+{
+    public function run()
+    {
+        $isMatch = mb_strpos('abc', 'a', 1) !== false;
+    }
+}
+?>
+-----
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class OffsetStrpos
+{
+    public function run()
+    {
+        $isMatch = str_contains(mb_substr('abc', 1), 'a');
+    }
+}
+?>
diff --git a/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_variable_equal_strpos.php.inc b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_variable_equal_strpos.php.inc
new file mode 100644
index 00000000000..defaf7f1515
--- /dev/null
+++ b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_variable_equal_strpos.php.inc
@@ -0,0 +1,27 @@
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class OffsetVariableStrpos
+{
+    public function run()
+    {
+        $offset = 1;
+        $isMatch = mb_strpos('abc', 'a', $offset) != false;
+    }
+}
+?>
+-----
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class OffsetVariableStrpos
+{
+    public function run()
+    {
+        $offset = 1;
+        $isMatch = str_contains(mb_substr('abc', $offset), 'a');
+    }
+}
+?>
diff --git a/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_variable_strpos.php.inc b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_variable_strpos.php.inc
new file mode 100644
index 00000000000..9b4945425dc
--- /dev/null
+++ b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_variable_strpos.php.inc
@@ -0,0 +1,27 @@
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class OffsetVariableStrpos
+{
+    public function run()
+    {
+        $offset = 1;
+        $isMatch = mb_strpos('abc', 'a', $offset) !== false;
+    }
+}
+?>
+-----
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class OffsetVariableStrpos
+{
+    public function run()
+    {
+        $offset = 1;
+        $isMatch = str_contains(mb_substr('abc', $offset), 'a');
+    }
+}
+?>
diff --git a/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_variable_zero_equal_strpos.php.inc b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_variable_zero_equal_strpos.php.inc
new file mode 100644
index 00000000000..ff3e1bc7e9c
--- /dev/null
+++ b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_variable_zero_equal_strpos.php.inc
@@ -0,0 +1,27 @@
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class OffsetVariableZeroStrpos
+{
+    public function run()
+    {
+        $offset = 0;
+        $isMatch = mb_strpos('abc', 'a', $offset) != false;
+    }
+}
+?>
+-----
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class OffsetVariableZeroStrpos
+{
+    public function run()
+    {
+        $offset = 0;
+        $isMatch = str_contains(mb_substr('abc', $offset), 'a');
+    }
+}
+?>
diff --git a/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_variable_zero_strpos.php.inc b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_variable_zero_strpos.php.inc
new file mode 100644
index 00000000000..c7cac64b729
--- /dev/null
+++ b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_variable_zero_strpos.php.inc
@@ -0,0 +1,27 @@
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class OffsetVariableZeroStrpos
+{
+    public function run()
+    {
+        $offset = 0;
+        $isMatch = mb_strpos('abc', 'a', $offset) !== false;
+    }
+}
+?>
+-----
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class OffsetVariableZeroStrpos
+{
+    public function run()
+    {
+        $offset = 0;
+        $isMatch = str_contains(mb_substr('abc', $offset), 'a');
+    }
+}
+?>
diff --git a/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_zero_equal_strpos.php.inc b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_zero_equal_strpos.php.inc
new file mode 100644
index 00000000000..54cf829f71e
--- /dev/null
+++ b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_zero_equal_strpos.php.inc
@@ -0,0 +1,25 @@
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class OffsetZeroStrpos
+{
+    public function run()
+    {
+        $isMatch = mb_strpos('abc', 'a', 0) != false;
+    }
+}
+?>
+-----
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class OffsetZeroStrpos
+{
+    public function run()
+    {
+        $isMatch = str_contains('abc', 'a');
+    }
+}
+?>
diff --git a/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_zero_strpos.php.inc b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_zero_strpos.php.inc
new file mode 100644
index 00000000000..7938e5ce99e
--- /dev/null
+++ b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/offset_zero_strpos.php.inc
@@ -0,0 +1,25 @@
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class OffsetZeroStrpos
+{
+    public function run()
+    {
+        $isMatch = mb_strpos('abc', 'a', 0) !== false;
+    }
+}
+?>
+-----
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class OffsetZeroStrpos
+{
+    public function run()
+    {
+        $isMatch = str_contains('abc', 'a');
+    }
+}
+?>
diff --git a/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/strpos_equal.php.inc b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/strpos_equal.php.inc
new file mode 100644
index 00000000000..a6129f96ced
--- /dev/null
+++ b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/strpos_equal.php.inc
@@ -0,0 +1,27 @@
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class IdenticalStrpos
+{
+    public function run()
+    {
+        $isMatch = mb_strpos('abc', 'a') == false;
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class IdenticalStrpos
+{
+    public function run()
+    {
+        $isMatch = !str_contains('abc', 'a');
+    }
+}
+
+?>
diff --git a/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/strstr.php.inc b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/strstr.php.inc
new file mode 100644
index 00000000000..613b9fb4480
--- /dev/null
+++ b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/strstr.php.inc
@@ -0,0 +1,27 @@
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class Strstr
+{
+    public function run()
+    {
+        $isMatch = mb_strstr('abc', 'a') !== false;
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class Strstr
+{
+    public function run()
+    {
+        $isMatch = str_contains('abc', 'a');
+    }
+}
+
+?>
diff --git a/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/strstr_equal.php.inc b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/strstr_equal.php.inc
new file mode 100644
index 00000000000..039c4b8949e
--- /dev/null
+++ b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/strstr_equal.php.inc
@@ -0,0 +1,27 @@
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class Strstr
+{
+    public function run()
+    {
+        $isMatch = mb_strstr('abc', 'a') != false;
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\Fixture;
+
+class Strstr
+{
+    public function run()
+    {
+        $isMatch = str_contains('abc', 'a');
+    }
+}
+
+?>
diff --git a/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/the_other_way.php.inc b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/the_other_way.php.inc
new file mode 100644
index 00000000000..f61ee8b3b4a
--- /dev/null
+++ b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/the_other_way.php.inc
@@ -0,0 +1,27 @@
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\StrContainsRector\Fixture;
+
+class TheOtherWay
+{
+    public function run()
+    {
+        $isMatch = false !== mb_strpos('abc', 'a');
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\StrContainsRector\Fixture;
+
+class TheOtherWay
+{
+    public function run()
+    {
+        $isMatch = str_contains('abc', 'a');
+    }
+}
+
+?>
diff --git a/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/the_other_way_equal.php.inc b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/the_other_way_equal.php.inc
new file mode 100644
index 00000000000..2e7ef24f8ad
--- /dev/null
+++ b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/Fixture/the_other_way_equal.php.inc
@@ -0,0 +1,27 @@
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\StrContainsRector\Fixture;
+
+class TheOtherWay
+{
+    public function run()
+    {
+        $isMatch = false != mb_strpos('abc', 'a');
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\StrContainsRector\Fixture;
+
+class TheOtherWay
+{
+    public function run()
+    {
+        $isMatch = str_contains('abc', 'a');
+    }
+}
+
+?>
diff --git a/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/MbStrContainsRectorTest.php b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/MbStrContainsRectorTest.php
new file mode 100644
index 00000000000..6c7f78b1f46
--- /dev/null
+++ b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/MbStrContainsRectorTest.php
@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector;
+
+use Iterator;
+use PHPUnit\Framework\Attributes\DataProvider;
+use Rector\Testing\PHPUnit\AbstractRectorTestCase;
+
+final class MbStrContainsRectorTest extends AbstractRectorTestCase
+{
+    #[DataProvider('provideData')]
+    public function test(string $filePath): void
+    {
+        $this->doTestFile($filePath);
+    }
+
+    public static function provideData(): Iterator
+    {
+        return self::yieldFilesFromDirectory(__DIR__ . '/Fixture');
+    }
+
+    public function provideConfigFilePath(): string
+    {
+        return __DIR__ . '/config/configured_rule.php';
+    }
+}
diff --git a/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/config/configured_rule.php b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/config/configured_rule.php
new file mode 100644
index 00000000000..559d668df47
--- /dev/null
+++ b/rules-tests/Php80/Rector/NotIdentical/MbStrContainsRector/config/configured_rule.php
@@ -0,0 +1,13 @@
+<?php
+
+declare(strict_types=1);
+
+use Rector\Config\RectorConfig;
+use Rector\Php80\Rector\NotIdentical\MbStrContainsRector;
+use Rector\ValueObject\PhpVersion;
+
+return static function (RectorConfig $rectorConfig): void {
+    $rectorConfig->phpVersion(PhpVersion::PHP_80);
+
+    $rectorConfig->rule(MbStrContainsRector::class);
+};
diff --git a/rules/Php80/NodeResolver/StrFalseComparisonResolver.php b/rules/Php80/NodeResolver/StrFalseComparisonResolver.php
new file mode 100644
index 00000000000..9bc44372491
--- /dev/null
+++ b/rules/Php80/NodeResolver/StrFalseComparisonResolver.php
@@ -0,0 +1,58 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\Php80\NodeResolver;
+
+use PhpParser\Node\Expr\BinaryOp\Equal;
+use PhpParser\Node\Expr\BinaryOp\Identical;
+use PhpParser\Node\Expr\BinaryOp\NotEqual;
+use PhpParser\Node\Expr\BinaryOp\NotIdentical;
+use PhpParser\Node\Expr\FuncCall;
+use Rector\NodeNameResolver\NodeNameResolver;
+use Rector\PhpParser\Node\Value\ValueResolver;
+
+final readonly class StrFalseComparisonResolver
+{
+    public function __construct(
+        private ValueResolver $valueResolver,
+        private NodeNameResolver $nodeNameResolver
+    ) {
+    }
+
+    /**
+     * @param string[] $oldStrFuncNames
+     */
+    public function resolve(Identical | NotIdentical | Equal | NotEqual $expr, array $oldStrFuncNames): ?FuncCall
+    {
+        if ($this->valueResolver->isFalse($expr->left)) {
+            if (! $expr->right instanceof FuncCall) {
+                return null;
+            }
+
+            if (! $this->nodeNameResolver->isNames($expr->right, $oldStrFuncNames)) {
+                return null;
+            }
+
+            /** @var FuncCall $funcCall */
+            $funcCall = $expr->right;
+            return $funcCall;
+        }
+
+        if ($this->valueResolver->isFalse($expr->right)) {
+            if (! $expr->left instanceof FuncCall) {
+                return null;
+            }
+
+            if (! $this->nodeNameResolver->isNames($expr->left, $oldStrFuncNames)) {
+                return null;
+            }
+
+            /** @var FuncCall $funcCall */
+            $funcCall = $expr->left;
+            return $funcCall;
+        }
+
+        return null;
+    }
+}
diff --git a/rules/Php80/Rector/NotIdentical/MbStrContainsRector.php b/rules/Php80/Rector/NotIdentical/MbStrContainsRector.php
new file mode 100644
index 00000000000..ac0ba3cb985
--- /dev/null
+++ b/rules/Php80/Rector/NotIdentical/MbStrContainsRector.php
@@ -0,0 +1,135 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\Php80\Rector\NotIdentical;
+
+use PhpParser\Node;
+use PhpParser\Node\Arg;
+use PhpParser\Node\Expr;
+use PhpParser\Node\Expr\BinaryOp\Equal;
+use PhpParser\Node\Expr\BinaryOp\Identical;
+use PhpParser\Node\Expr\BinaryOp\NotEqual;
+use PhpParser\Node\Expr\BinaryOp\NotIdentical;
+use PhpParser\Node\Expr\BooleanNot;
+use PhpParser\Node\Expr\FuncCall;
+use PhpParser\Node\Name;
+use PhpParser\Node\Scalar\Int_;
+use Rector\Php80\NodeResolver\StrFalseComparisonResolver;
+use Rector\Rector\AbstractRector;
+use Rector\ValueObject\PhpVersionFeature;
+use Rector\ValueObject\PolyfillPackage;
+use Rector\VersionBonding\Contract\MinPhpVersionInterface;
+use Rector\VersionBonding\Contract\RelatedPolyfillInterface;
+use Symplify\RuleDocGenerator\ValueObject\CodeSample\CodeSample;
+use Symplify\RuleDocGenerator\ValueObject\RuleDefinition;
+
+/**
+ * @see \Rector\Tests\Php80\Rector\NotIdentical\MbStrContainsRector\MbStrContainsRectorTest
+ */
+final class MbStrContainsRector extends AbstractRector implements MinPhpVersionInterface, RelatedPolyfillInterface
+{
+    /**
+     * @var string[]
+     */
+    private const OLD_STR_NAMES = ['mb_strpos', 'mb_strstr'];
+
+    public function __construct(
+        private readonly StrFalseComparisonResolver $strFalseComparisonResolver
+    ) {
+    }
+
+    public function provideMinPhpVersion(): int
+    {
+        return PhpVersionFeature::STR_CONTAINS;
+    }
+
+    public function getRuleDefinition(): RuleDefinition
+    {
+        return new RuleDefinition(
+            'Replace mb_strpos() !== false and mb_strstr()  with str_contains()',
+            [
+                new CodeSample(
+                    <<<'CODE_SAMPLE'
+class SomeClass
+{
+    public function run()
+    {
+        return mb_strpos('abc', 'a') !== false;
+    }
+}
+CODE_SAMPLE
+                    ,
+                    <<<'CODE_SAMPLE'
+class SomeClass
+{
+    public function run()
+    {
+        return str_contains('abc', 'a');
+    }
+}
+CODE_SAMPLE
+                ),
+            ]
+        );
+    }
+
+    /**
+     * @return array<class-string<Node>>
+     */
+    public function getNodeTypes(): array
+    {
+        return [Identical::class, NotIdentical::class, Equal::class, NotEqual::class];
+    }
+
+    /**
+     * @param Identical|NotIdentical|Equal|NotEqual $node
+     */
+    public function refactor(Node $node): ?Node
+    {
+        $funcCall = $this->strFalseComparisonResolver->resolve($node, self::OLD_STR_NAMES);
+
+        if (! $funcCall instanceof FuncCall) {
+            return null;
+        }
+
+        if ($funcCall->isFirstClassCallable()) {
+            return null;
+        }
+
+        if (isset($funcCall->getArgs()[2])) {
+            $secondArg = $funcCall->getArgs()[2];
+
+            if ($this->isName($funcCall->name, 'mb_strpos') && ! $this->isIntegerZero($secondArg->value)) {
+                $funcCall->args[0] = new Arg($this->nodeFactory->createFuncCall(
+                    'mb_substr',
+                    [$funcCall->args[0], $secondArg]
+                ));
+            }
+
+            unset($funcCall->args[2]);
+        }
+
+        $funcCall->name = new Name('str_contains');
+
+        if ($node instanceof Identical || $node instanceof Equal) {
+            return new BooleanNot($funcCall);
+        }
+
+        return $funcCall;
+    }
+
+    public function providePolyfillPackage(): string
+    {
+        return PolyfillPackage::PHP_80;
+    }
+
+    private function isIntegerZero(Expr $expr): bool
+    {
+        if (! $expr instanceof Int_) {
+            return false;
+        }
+
+        return $expr->value === 0;
+    }
+}
diff --git a/rules/Php80/Rector/NotIdentical/StrContainsRector.php b/rules/Php80/Rector/NotIdentical/StrContainsRector.php
index 035e2ec6d8e..3d3f3710bf6 100644
--- a/rules/Php80/Rector/NotIdentical/StrContainsRector.php
+++ b/rules/Php80/Rector/NotIdentical/StrContainsRector.php
@@ -15,6 +15,7 @@
 use PhpParser\Node\Expr\FuncCall;
 use PhpParser\Node\Name;
 use PhpParser\Node\Scalar\Int_;
+use Rector\Php80\NodeResolver\StrFalseComparisonResolver;
 use Rector\PhpParser\Node\Value\ValueResolver;
 use Rector\Rector\AbstractRector;
 use Rector\ValueObject\PhpVersionFeature;
@@ -35,7 +36,7 @@ final class StrContainsRector extends AbstractRector implements MinPhpVersionInt
     private const OLD_STR_NAMES = ['strpos', 'strstr'];
 
     public function __construct(
-        private readonly ValueResolver $valueResolver
+        private readonly StrFalseComparisonResolver $strFalseComparisonResolver
     ) {
     }
 
@@ -87,7 +88,7 @@ public function getNodeTypes(): array
      */
     public function refactor(Node $node): ?Node
     {
-        $funcCall = $this->matchIdenticalOrNotIdenticalToFalse($node);
+        $funcCall = $this->strFalseComparisonResolver->resolve($node, self::OLD_STR_NAMES);
 
         if (! $funcCall instanceof FuncCall) {
             return null;
@@ -124,39 +125,6 @@ public function providePolyfillPackage(): string
         return PolyfillPackage::PHP_80;
     }
 
-    private function matchIdenticalOrNotIdenticalToFalse(Identical | NotIdentical | Equal | NotEqual $expr): ?FuncCall
-    {
-        if ($this->valueResolver->isFalse($expr->left)) {
-            if (! $expr->right instanceof FuncCall) {
-                return null;
-            }
-
-            if (! $this->isNames($expr->right, self::OLD_STR_NAMES)) {
-                return null;
-            }
-
-            /** @var FuncCall $funcCall */
-            $funcCall = $expr->right;
-            return $funcCall;
-        }
-
-        if ($this->valueResolver->isFalse($expr->right)) {
-            if (! $expr->left instanceof FuncCall) {
-                return null;
-            }
-
-            if (! $this->isNames($expr->left, self::OLD_STR_NAMES)) {
-                return null;
-            }
-
-            /** @var FuncCall $funcCall */
-            $funcCall = $expr->left;
-            return $funcCall;
-        }
-
-        return null;
-    }
-
     private function isIntegerZero(Expr $expr): bool
     {
         if (! $expr instanceof Int_) {