If you've arrived at this page, presumably you're here to register your warranty. That means we need to say congratulations on your purchase of an Ibis. Either that or we need to ask you what are you doing here?
Please do register. It helps us out. Our suspension frames require a serial number for both the frame and swingarm.
Serial numbers on the front triangle can be found under the bottom bracket. For the swingarm, if you're having a hard time locating the serial, it might be located under the linkage: