URL Decoding in PHP

Actually, you get the desired output, but it is not interpreted as UTF-8. If this is on an HTTP application, you should send a header or a meta tag (or both) which would tell the client to use UTF-8.

Edit: for example:

// replace text/html with the content type you're using
header('Content-Type: text/html; charset=UTF-8');

Your string is also UTF-8 encoded. This will work:

echo utf8_decode(urldecode("Ant%C3%B4nio+Carlos+Jobim"));

Output: "Antônio Carlos Jobim".

when I do

<?php
echo urldecode("Ant%C3%B4nio+Carlos+Jobim");
?>

Its display correctly in my browser like

Antônio Carlos Jobim

I have tested with XAMPP

another option is:

<?php
$smthing = 'http%3A%2F%2Fmysite.com';
$smthing = preg_replace("/%u([0-9a-f]{3,4})/i","&#x\\1;",urldecode($smthing)); 
$smthing = html_entity_decode($smthing,null,'UTF-8');
echo $smthing;
?>

output becomes : http://mysite.com