diff --git a/.sdkmanrc b/.sdkmanrc
index d2635abfaf..8e05285ec6 100644
--- a/.sdkmanrc
+++ b/.sdkmanrc
@@ -1,3 +1,3 @@
 # Enable auto-env through the sdkman_auto_env config
 # Add key=value pairs of SDKs to use below
-java=21.0.5-tem
+java=21.0.7-tem
diff --git a/src/main/java/org/openrewrite/java/migrate/lang/ReplaceUnusedVariablesWithUnderscore.java b/src/main/java/org/openrewrite/java/migrate/lang/ReplaceUnusedVariablesWithUnderscore.java
new file mode 100644
index 0000000000..43680fef6a
--- /dev/null
+++ b/src/main/java/org/openrewrite/java/migrate/lang/ReplaceUnusedVariablesWithUnderscore.java
@@ -0,0 +1,111 @@
+/*
+ * Copyright 2025 the original author or authors.
+ * <p>
+ * Licensed under the Moderne Source Available License (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * <p>
+ * https://docs.moderne.io/licensing/moderne-source-available-license
+ * <p>
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.openrewrite.java.migrate.lang;
+
+import lombok.EqualsAndHashCode;
+import lombok.Value;
+import org.openrewrite.ExecutionContext;
+import org.openrewrite.Preconditions;
+import org.openrewrite.Recipe;
+import org.openrewrite.TreeVisitor;
+import org.openrewrite.java.JavaIsoVisitor;
+import org.openrewrite.java.RenameVariable;
+import org.openrewrite.java.search.SemanticallyEqual;
+import org.openrewrite.java.search.UsesJavaVersion;
+import org.openrewrite.java.tree.J;
+import org.openrewrite.java.tree.Statement;
+import org.openrewrite.staticanalysis.VariableReferences;
+
+import java.util.concurrent.atomic.AtomicBoolean;
+
+@EqualsAndHashCode(callSuper = false)
+@Value
+public class ReplaceUnusedVariablesWithUnderscore extends Recipe {
+
+    private static final String UNDERSCORE = "_";
+
+    @Override
+    public String getDisplayName() {
+        return "Replace unused variables with underscore";
+    }
+
+    @Override
+    public String getDescription() {
+        return "Replace unused variable declarations with underscore (_) for Java 22+. " +
+                "This includes unused variables in enhanced for loops, catch blocks, " +
+                "and lambda parameters where the variable is never referenced.";
+    }
+
+    @Override
+    public TreeVisitor<?, ExecutionContext> getVisitor() {
+        return Preconditions.check(new UsesJavaVersion<>(25), new JavaIsoVisitor<ExecutionContext>() {
+            @Override
+            public J.ForEachLoop visitForEachLoop(J.ForEachLoop forLoop, ExecutionContext ctx) {
+                J.ForEachLoop l = super.visitForEachLoop(forLoop, ctx);
+                Statement variable = l.getControl().getVariable();
+                if (variable instanceof J.VariableDeclarations) {
+                    for (J.VariableDeclarations.NamedVariable namedVariable : ((J.VariableDeclarations) variable).getVariables()) {
+                        renameVariableIfUnusedInContext(namedVariable, l.getBody());
+                    }
+                }
+                return l;
+            }
+
+            @Override
+            public J.Try.Catch visitCatch(J.Try.Catch _catch, ExecutionContext ctx) {
+                J.Try.Catch c = super.visitCatch(_catch, ctx);
+                for (J.VariableDeclarations.NamedVariable namedVariable : c.getParameter().getTree().getVariables()) {
+                    renameVariableIfUnusedInContext(namedVariable, c.getBody());
+                }
+                return c;
+            }
+
+            @Override
+            public J.Lambda visitLambda(J.Lambda lambda, ExecutionContext ctx) {
+                J.Lambda l = super.visitLambda(lambda, ctx);
+                for (J param : l.getParameters().getParameters()) {
+                    if (param instanceof J.VariableDeclarations) {
+                        for (J.VariableDeclarations.NamedVariable namedVariable : ((J.VariableDeclarations) param).getVariables()) {
+                            renameVariableIfUnusedInContext(namedVariable, l.getBody());
+                        }
+                    }
+                }
+                return l;
+            }
+
+            private void renameVariableIfUnusedInContext(J.VariableDeclarations.NamedVariable variable, J context) {
+                if (!UNDERSCORE.equals(variable.getName().getSimpleName()) &&
+                        VariableReferences.findRhsReferences(context, variable.getName()).isEmpty() &&
+                        !usedInModifyingUnary(variable.getName(), context)) {
+                    doAfterVisit(new RenameVariable<>(variable, UNDERSCORE));
+                }
+            }
+
+            private boolean usedInModifyingUnary(J.Identifier identifier, J context) {
+                return new JavaIsoVisitor<AtomicBoolean>() {
+                    @Override
+                    public J.Unary visitUnary(J.Unary unary, AtomicBoolean atomicBoolean) {
+                        if (unary.getOperator().isModifying() &&
+                                SemanticallyEqual.areEqual(identifier, unary.getExpression())) {
+                            atomicBoolean.set(true);
+                        }
+                        return super.visitUnary(unary, atomicBoolean);
+                    }
+                }.reduce(context, new AtomicBoolean(false)).get();
+            }
+        });
+    }
+}
diff --git a/src/main/resources/META-INF/rewrite/java-version-25.yml b/src/main/resources/META-INF/rewrite/java-version-25.yml
index 1bc043cf76..6b12e6bb39 100644
--- a/src/main/resources/META-INF/rewrite/java-version-25.yml
+++ b/src/main/resources/META-INF/rewrite/java-version-25.yml
@@ -28,6 +28,7 @@ recipeList:
   - org.openrewrite.java.migrate.UpgradeToJava21
   - org.openrewrite.java.migrate.UpgradeBuildToJava25
   - org.openrewrite.java.migrate.lang.MigrateProcessWaitForDuration
+  - org.openrewrite.java.migrate.lang.ReplaceUnusedVariablesWithUnderscore
   - org.openrewrite.java.migrate.util.MigrateInflaterDeflaterToClose
   - org.openrewrite.java.migrate.AccessController
   - org.openrewrite.java.migrate.RemoveSecurityPolicy
diff --git a/src/test/java/org/openrewrite/java/migrate/lang/ReplaceUnusedVariablesWithUnderscoreTest.java b/src/test/java/org/openrewrite/java/migrate/lang/ReplaceUnusedVariablesWithUnderscoreTest.java
new file mode 100644
index 0000000000..070802055c
--- /dev/null
+++ b/src/test/java/org/openrewrite/java/migrate/lang/ReplaceUnusedVariablesWithUnderscoreTest.java
@@ -0,0 +1,443 @@
+/*
+ * Copyright 2025 the original author or authors.
+ * <p>
+ * Licensed under the Moderne Source Available License (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * <p>
+ * https://docs.moderne.io/licensing/moderne-source-available-license
+ * <p>
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.openrewrite.java.migrate.lang;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+import org.openrewrite.DocumentExample;
+import org.openrewrite.java.JavaParser;
+import org.openrewrite.test.RecipeSpec;
+import org.openrewrite.test.RewriteTest;
+
+import static org.openrewrite.java.Assertions.java;
+import static org.openrewrite.java.Assertions.javaVersion;
+
+class ReplaceUnusedVariablesWithUnderscoreTest implements RewriteTest {
+
+    @Override
+    public void defaults(RecipeSpec spec) {
+        spec
+          .recipe(new ReplaceUnusedVariablesWithUnderscore())
+          .parser(JavaParser.fromJavaVersion())
+          .allSources(s -> s.markers(javaVersion(25)));
+    }
+
+    @DocumentExample
+    @Test
+    void replaceUnusedForEachVariable() {
+        rewriteRun(
+          //language=java
+          java(
+            """
+              import java.util.List;
+
+              class Test {
+                  int countOrders(List<String> orders) {
+                      int total = 0;
+                      for (String order : orders) {
+                          total++;
+                      }
+                      return total;
+                  }
+              }
+              """,
+            """
+              import java.util.List;
+
+              class Test {
+                  int countOrders(List<String> orders) {
+                      int total = 0;
+                      for (String _ : orders) {
+                          total++;
+                      }
+                      return total;
+                  }
+              }
+              """
+          )
+        );
+    }
+
+    @Test
+    void doNotReplaceUsedForEachVariable() {
+        rewriteRun(
+          //language=java
+          java(
+            """
+              import java.util.List;
+
+              class Test {
+                  void processOrders(List<String> orders) {
+                      for (String order : orders) {
+                          System.out.println(order);
+                      }
+                  }
+              }
+              """
+          )
+        );
+    }
+
+    @Test
+    void replaceUnusedCatchVariable() {
+        rewriteRun(
+          //language=java
+          java(
+            """
+              class Test {
+                  void parseNumber(String s) {
+                      try {
+                          Integer.parseInt(s);
+                      } catch (NumberFormatException ex) {
+                          System.out.println("Bad number: " + s);
+                      }
+                  }
+              }
+              """,
+            """
+              class Test {
+                  void parseNumber(String s) {
+                      try {
+                          Integer.parseInt(s);
+                      } catch (NumberFormatException _) {
+                          System.out.println("Bad number: " + s);
+                      }
+                  }
+              }
+              """
+          )
+        );
+    }
+
+    @Test
+    void doNotReplaceUsedCatchVariable() {
+        rewriteRun(
+          //language=java
+          java(
+            """
+              class Test {
+                  void parseNumber(String s) {
+                      try {
+                          Integer.parseInt(s);
+                      } catch (NumberFormatException ex) {
+                          System.out.println("Error: " + ex.getMessage());
+                      }
+                  }
+              }
+              """
+          )
+        );
+    }
+
+    @Test
+    void replaceUnusedLambdaParameter() {
+        rewriteRun(
+          //language=java
+          java(
+            """
+              import java.util.stream.Stream;
+              import java.util.stream.Collectors;
+
+              class Test {
+                  void example() {
+                      Stream.of("a", "b", "c")
+                          .collect(Collectors.toMap(String::toUpperCase, item -> "NODATA"));
+                  }
+              }
+              """,
+            """
+              import java.util.stream.Stream;
+              import java.util.stream.Collectors;
+
+              class Test {
+                  void example() {
+                      Stream.of("a", "b", "c")
+                          .collect(Collectors.toMap(String::toUpperCase, _ -> "NODATA"));
+                  }
+              }
+              """
+          )
+        );
+    }
+
+    @Test
+    void doNotReplaceUsedLambdaParameter() {
+        rewriteRun(
+          //language=java
+          java(
+            """
+              import java.util.stream.Stream;
+              import java.util.stream.Collectors;
+
+              class Test {
+                  void example() {
+                      Stream.of("a", "b", "c")
+                          .collect(Collectors.toMap(String::toUpperCase, item -> item.length()));
+                  }
+              }
+              """
+          )
+        );
+    }
+
+    @Test
+    void noChangeOnJava21() {
+        rewriteRun(
+          spec -> spec.allSources(s -> s.markers(javaVersion(21))),
+          //language=java
+          java(
+            """
+              import java.util.List;
+
+              class Test {
+                  int countOrders(List<String> orders) {
+                      int total = 0;
+                      for (String order : orders) {
+                          total++;
+                      }
+                      return total;
+                  }
+              }
+              """
+          )
+        );
+    }
+
+    @Test
+    void handleNestedLoops() {
+        rewriteRun(
+          //language=java
+          java(
+            """
+              import java.util.List;
+
+              class Test {
+                  void example(List<List<String>> matrix) {
+                      for (List<String> row : matrix) {
+                          for (String item : row) {
+                              System.out.println();
+                          }
+                      }
+                  }
+              }
+              """,
+            """
+              import java.util.List;
+
+              class Test {
+                  void example(List<List<String>> matrix) {
+                      for (List<String> row : matrix) {
+                          for (String _ : row) {
+                              System.out.println();
+                          }
+                      }
+                  }
+              }
+              """
+          )
+        );
+    }
+
+    @Test
+    void handleNestedLoopsBothUnused() {
+        rewriteRun(
+          //language=java
+          java(
+            """
+              import java.util.List;
+
+              class Test {
+                  void test(List<List<String>> matrix) {
+                      int count = 0;
+                      for (List<String> row : matrix) {
+                          for (String item : matrix.get(0)) {
+                              count++;
+                          }
+                      }
+                  }
+              }
+              """,
+            """
+              import java.util.List;
+
+              class Test {
+                  void test(List<List<String>> matrix) {
+                      int count = 0;
+                      for (List<String> _ : matrix) {
+                          for (String _ : matrix.get(0)) {
+                              count++;
+                          }
+                      }
+                  }
+              }
+              """
+          )
+        );
+    }
+
+    @Test
+    void replaceBiConsumerBothParametersUnused() {
+        rewriteRun(
+          //language=java
+          java(
+            """
+              import java.util.function.BiConsumer;
+
+              class Test {
+                  void test() {
+                      BiConsumer<String, String> consumer = (first, second) -> System.out.println();
+                  }
+              }
+              """,
+            """
+              import java.util.function.BiConsumer;
+
+              class Test {
+                  void test() {
+                      BiConsumer<String, String> consumer = (_, _) -> System.out.println();
+                  }
+              }
+              """
+          )
+        );
+    }
+
+    @Test
+    void doNotReplaceUsedInMethodReference() {
+        rewriteRun(
+          //language=java
+          java(
+            """
+              import java.util.stream.Stream;
+
+              class Test {
+                  void test() {
+                      Stream.of("a").forEach(item -> System.out.println(item.toString()));
+                  }
+              }
+              """
+          )
+        );
+    }
+
+    @Test
+    void replaceUnusedInNestedLambda() {
+        rewriteRun(
+          //language=java
+          java(
+            """
+              import java.util.stream.Stream;
+
+              class Test {
+                  void test() {
+                      Stream.of("a").forEach(outer -> {
+                          Stream.of("b").forEach(inner -> System.out.println());
+                      });
+                  }
+              }
+              """,
+            """
+              import java.util.stream.Stream;
+
+              class Test {
+                  void test() {
+                      Stream.of("a").forEach(_ -> {
+                          Stream.of("b").forEach(_ -> System.out.println());
+                      });
+                  }
+              }
+              """
+          )
+        );
+    }
+
+    @Test
+    void doNotReplaceWhenOuterVariableUsedInInnerLambda() {
+        rewriteRun(
+          //language=java
+          java(
+            """
+              import java.util.stream.Stream;
+
+              class Test {
+                  void test() {
+                      Stream.of("a").forEach(outer -> {
+                          Stream.of("b").forEach(inner -> System.out.println(outer));
+                      });
+                  }
+              }
+              """,
+            """
+              import java.util.stream.Stream;
+
+              class Test {
+                  void test() {
+                      Stream.of("a").forEach(outer -> {
+                          Stream.of("b").forEach(_ -> System.out.println(outer));
+                      });
+                  }
+              }
+              """
+          )
+        );
+    }
+
+    @ParameterizedTest
+    @ValueSource(strings = {
+      "++number; // Weird, but allowed",
+      "number++;",
+    })
+    void doNotReplaceModifyingOperator(String body) {
+        rewriteRun(
+          //language=java
+          java(
+            """
+              import java.util.List;
+              import java.util.stream.Stream;
+
+              class Test {
+                  int forloop(List<Integer> numbers) {
+                      for (int number : numbers) {
+                          %s
+                      }
+                  }
+              }
+              """.formatted(body)
+          )
+        );
+    }
+
+    @Test
+    void doNotReplaceUnrelatedVariables() {
+        rewriteRun(
+          //language=java
+          java(
+            """
+              import java.util.List;
+
+              class Test {
+                  int countOrders(List<String> orders) {
+                      for (String order : orders) {
+                          String o = order;
+                      }
+                  }
+              }
+              """
+          )
+        );
+    }
+}