$re = '/^\+?[0-9()\s-]{8,25}[0-9]$/m';
$str = '+123456789
+1 234 567 8910
1 (234) 567 8910
1 (234) 567-8910
+1-234-567-8910
1 234 567 8910
"123456789"
\'123456789\'
/123456789/
';
preg_match_all($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