diff --git a/mock.go b/mock.go
index 7255aff..f302b0f 100644
--- a/mock.go
+++ b/mock.go
@@ -454,9 +454,10 @@ func (m *Mock) newTrap(fn clockFunction, tags []string) *Trap {
 	if !m.testOver {
 		m.logger.Logf("Mock Clock - Trap %s(..., %v)", fn, tags)
 	}
+	// Copy tags because the caller may reuse its slice while the trap still matches calls.
 	tr := &Trap{
 		fn:    fn,
-		tags:  tags,
+		tags:  slices.Clone(tags),
 		mock:  m,
 		calls: make(chan *apiCall),
 		done:  make(chan struct{}),
@@ -728,9 +729,11 @@ func withDuration(d time.Duration) callArg {
 }
 
 func newCall(fn clockFunction, tags []string, args ...callArg) *apiCall {
+	// Copy tags because the caller may reuse its slice after the call returns, while a trapped call
+	// still exposes them as Call.Tags.
 	c := &apiCall{
 		fn:       fn,
-		Tags:     tags,
+		Tags:     slices.Clone(tags),
 		complete: make(chan struct{}),
 	}
 	for _, a := range args {
diff --git a/mock_test.go b/mock_test.go
index 7bc822d..17d7ea4 100644
--- a/mock_test.go
+++ b/mock_test.go
@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"os"
 	"runtime/pprof"
+	"slices"
 	"strings"
 	"testing"
 	"time"
@@ -414,6 +415,33 @@ func Test_UnreleasedCalls(t *testing.T) {
 	})
 }
 
+func TestTags_CallerReusesSlice(t *testing.T) {
+	t.Parallel()
+	testCtx, testCancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer testCancel()
+	mClock := quartz.NewMock(t)
+
+	trapTags := []string{"foo"}
+	trap := mClock.Trap().Now(trapTags...)
+	defer trap.Close()
+	trapTags[0] = "reused"
+
+	done := make(chan struct{})
+	go func() {
+		defer close(done)
+		callTags := []string{"foo"}
+		mClock.Now(callTags...)
+		callTags[0] = "reused"
+	}()
+
+	call := trap.MustWait(testCtx)
+	call.MustRelease(testCtx)
+	<-done
+	if want := []string{"foo"}; !slices.Equal(call.Tags, want) {
+		t.Fatalf("expected tags %v, got %v", want, call.Tags)
+	}
+}
+
 func Test_WithLogger(t *testing.T) {
 	t.Parallel()