$re = '/(?<![^a-zA-Z\s])((\+|00(\s|\s?-\s?)?)31(\s|\s?-\s?)?(\(0\)[-\s]?)?|0)[1-9]((\s|\s?-\s?)?[0-9])((\s|\s?-\s?)?[0-9])((\s|\s?-\s?)?[0-9])\s?[0-9]\s?[0-9]\s?[0-9]\s?[0-9]\s?[0-9](?![^a-zA-Z\s])/m';
$str = 'Mijn telefoonnnummer is 0612131415
Mijn telefoonnnummer is 06-12345678
Mijn telefoonnummer0612131415email
Is shouldn\'t detect
000006121314150000
-0612131415-
00-0612131415-00';
preg_match_all($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