diff --git a/keywords_format.go b/keywords_format.go
index 94d5b7b..ff8a6f9 100644
--- a/keywords_format.go
+++ b/keywords_format.go
@@ -199,14 +199,14 @@ func isValidIPv6(ipv6 string) error {
 // according to [RFC3987].
 // https://tools.ietf.org/html/rfc3987
 func isValidIriRef(iriRef string) error {
-	return nil
+	return isValidURIRef(iriRef)
 }
 
 // A string instance is a valid against "iri" if it is a valid IRI,
 // according to [RFC3987].
 // https://tools.ietf.org/html/rfc3987
 func isValidIri(iri string) error {
-	return nil
+	return isValidURI(iri)
 }
 
 // A string instance is a valid against "json-pointer" if it is a
@@ -240,6 +240,9 @@ func isValidJSONPointer(jsonPointer string) error {
 // http://json-schema.org/latest/json-schema-validation.html#regexInterop
 // https://tools.ietf.org/html/rfc7159
 func isValidRegex(regex string) error {
+	if _, err := regexp.Compile(regex); err != nil {
+		return fmt.Errorf("invalid regex expression")
+	}
 	return nil
 }
 
diff --git a/schema_test.go b/schema_test.go
index f0386d8..02287bc 100644
--- a/schema_test.go
+++ b/schema_test.go
@@ -286,7 +286,7 @@ func TestDraft7(t *testing.T) {
 		"testdata/draft7/optional/format/date-time.json",
 		"testdata/draft7/optional/format/hostname.json",
 		"testdata/draft7/optional/format/ipv4.json",
-		// "testdata/draft7/optional/format/iri.json",
+		"testdata/draft7/optional/format/iri.json",
 		"testdata/draft7/optional/format/relative-json-pointer.json",
 		"testdata/draft7/optional/format/uri-template.json",
 		"testdata/draft7/optional/format/date.json",
@@ -297,8 +297,8 @@ func TestDraft7(t *testing.T) {
 		"testdata/draft7/optional/format/uri.json",
 		"testdata/draft7/optional/format/email.json",
 		"testdata/draft7/optional/format/idn-hostname.json",
-		// "testdata/draft7/optional/format/iri-reference.json",
-		// "testdata/draft7/optional/format/regex.json",
+		"testdata/draft7/optional/format/iri-reference.json",
+		"testdata/draft7/optional/format/regex.json",
 		"testdata/draft7/optional/format/uri-reference.json",
 	})
 }