The USB port lines up.

The headphone port is closer to the centre on the s3 so that doesn't match.

The camera on the n4 is in the same spot as the S3's flash so that works.

The volume buttons on the side are almost the same (about 3mm higher on the N4 vs the S3) so you can still adjust the volume.

The power button is not accessible with this case and doesn't line up at all any way by the looks of things.

I was looking for a sturdy waterproof, touch case for my phone for cycling. There wasn't one specific for the Nexus 4 that met my criteria so the only option was to look at existing Galaxy S3 GT-i9300 accessory's due to the phone dimensions being so similar. I found the Easy Fit IPX4 Waterproof Tough Case Motorcycle Bike Handlebar Mount Galaxy S3 GT-i9300 from amazon.In short it's almost an exact fit but with the following comments:The phones dimensions are the same in width and height but with these points to remeber:The case itself is great and keeps the phone very secure to the handle bars. A simple quick release mechanism to remove the phone with the case is there as well. Its great for using google maps and navigation. Not much else to say really.The only modification I plan on making is a small hole to access the N4's headphone socket.I've attached some pics so people can get a good idea of what it all looks like.Hope I helped