diff --git a/integration-tests/nghttpx_http3_test.go b/integration-tests/nghttpx_http3_test.go
index 9bac1652..28478365 100644
--- a/integration-tests/nghttpx_http3_test.go
+++ b/integration-tests/nghttpx_http3_test.go
@@ -246,3 +246,88 @@ func TestH3H1AffinityCookieTLS(t *testing.T) {
 		t.Errorf("Set-Cookie: %v; want pattern %v", got, pattern)
 	}
 }
+
+// TestH3H2ReqPhaseReturn tests mruby request phase hook returns
+// custom response.
+func TestH3H2ReqPhaseReturn(t *testing.T) {
+	opts := options{
+		args: []string{
+			"--http2-bridge",
+			"--mruby-file=" + testDir + "/req-return.rb",
+		},
+		handler: func(w http.ResponseWriter, r *http.Request) {
+			t.Fatalf("request should not be forwarded")
+		},
+		quic: true,
+	}
+	st := newServerTester(t, opts)
+	defer st.Close()
+
+	res, err := st.http3(requestParam{
+		name: "TestH3H2ReqPhaseReturn",
+	})
+	if err != nil {
+		t.Fatalf("Error st.http3() = %v", err)
+	}
+
+	if got, want := res.status, 404; got != want {
+		t.Errorf("status = %v; want %v", got, want)
+	}
+
+	hdtests := []struct {
+		k, v string
+	}{
+		{"content-length", "20"},
+		{"from", "mruby"},
+	}
+	for _, tt := range hdtests {
+		if got, want := res.header.Get(tt.k), tt.v; got != want {
+			t.Errorf("%v = %v; want %v", tt.k, got, want)
+		}
+	}
+
+	if got, want := string(res.body), "Hello World from req"; got != want {
+		t.Errorf("body = %v; want %v", got, want)
+	}
+}
+
+// TestH3H2RespPhaseReturn tests mruby response phase hook returns
+// custom response.
+func TestH3H2RespPhaseReturn(t *testing.T) {
+	opts := options{
+		args: []string{
+			"--http2-bridge",
+			"--mruby-file=" + testDir + "/resp-return.rb",
+		},
+		quic: true,
+	}
+	st := newServerTester(t, opts)
+	defer st.Close()
+
+	res, err := st.http3(requestParam{
+		name: "TestH3H2RespPhaseReturn",
+	})
+	if err != nil {
+		t.Fatalf("Error st.http3() = %v", err)
+	}
+
+	if got, want := res.status, 404; got != want {
+		t.Errorf("status = %v; want %v", got, want)
+	}
+
+	hdtests := []struct {
+		k, v string
+	}{
+		{"content-length", "21"},
+		{"from", "mruby"},
+	}
+	for _, tt := range hdtests {
+		if got, want := res.header.Get(tt.k), tt.v; got != want {
+			t.Errorf("%v = %v; want %v", tt.k, got, want)
+		}
+	}
+
+	if got, want := string(res.body), "Hello World from resp"; got != want {
+		t.Errorf("body = %v; want %v", got, want)
+	}
+}