$re = '/.*Voyage\:\\\\xa0{1}\s+([0-9]{4}[A-Z]{1}).*/';
$str = ' \\nSEASPAN LONCOMILLA\\n\\r\\n Voyage:\\xa0 1396S\\r\\n \\n\\n\\r\\n 10-Apr\\r\\n ALGECIRAS\\r\\n \\n\\n\\r\\n 01-May\\r\\n KRIBI\\r\\n \\n\\n\'';
preg_match($re, $str, $matches, PREG_OFFSET_CAPTURE, 0);
// Print the entire match result
var_dump($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