diff --git a/pkg/booking/public.go b/pkg/booking/public.go
index e03840a..1104e7d 100644
--- a/pkg/booking/public.go
+++ b/pkg/booking/public.go
@@ -256,7 +256,7 @@ func (f *bookingForm) Valid(ctx context.Context, conn *database.Conn, l *locale.
 		v.CheckMinLength(f.FullName, 1, l.GettextNoop("Full name must have at least one letter."))
 	}
 
-	if f.PostalCode.Val != "" {
+	if country != "" && f.PostalCode.Val != "" {
 		if _, err := v.CheckValidPostalCode(ctx, conn, f.PostalCode, country, l.GettextNoop("This postal code is not valid.")); err != nil {
 			return false, err
 		}