diff --git a/src/Validator.php b/src/Validator.php
index d276ba9..fc3e199 100644
--- a/src/Validator.php
+++ b/src/Validator.php
@@ -29,7 +29,7 @@ class Validator
         'GB' => '(\d{9}|\d{12}|(GD|HA)\d{3})',
         'HR' => '\d{11}',
         'HU' => '\d{8}',
-        'IE' => '([A-Z\d]{8}|[A-Z\d]{9})',
+        'IE' => '((\d{7}[A-Z]{1,2})|(\d[A-Z]\d{5}[A-Z]))',
         'IT' => '\d{11}',
         'LT' => '(\d{9}|\d{12})',
         'LU' => '\d{8}',
diff --git a/tests/ValidatorTest.php b/tests/ValidatorTest.php
index 1381327..847bc49 100644
--- a/tests/ValidatorTest.php
+++ b/tests/ValidatorTest.php
@@ -39,6 +39,8 @@ public function testValidateVatNumberFormat()
             'HU12345678',
             'HR12345678901',
             'IE1234567X',
+            'IE1X34567X',
+            'IE1234567XX',
             'IT12345678901',
             'LT123456789',
             'LU12345678',
@@ -78,6 +80,9 @@ public function testValidateVatNumberFormat()
             'HU1234567',
             'HR1234567890',
             'IE123456X',
+            'IE1X34567XX',
+            'IE12345678X',
+            'IE123456789',
             'IT1234567890',
             'LT12345678',
             'LU1234567',