$re = '/^(:?(\+)|(00))?(:?966)?+(5|05)([503649187])([0-9]{7})$/m';
$str = '+966555002871
00966555002871
0555339634
966555002871
05555557896';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php