Lisel
umm put it in water and find where the bubbles are coming from then buy a patch for it

KOHA
Mix sudzy dish wash in a spray bottle. Spray on the mattress and look for bubbles.

annie
got a pool? otherwise I agree, the sudsy water would be your next best bet

Caiman94941
I just blew up the airbed and then laid on it in a quiet room, I just moved along with my ear to the mattress and eventually heard the slight whistle of escaping air. Since I didn't have a patch kit, out came the duct tape...that took care of the leak. (But keep checking both sides because sometimes there is more than one leak)

MONA
Double check the seams with your finger or side of face to see if you can feel or hear the air come out. If that doesn't work you'll have use your bathtub filled with water and check the mattress section by section (kinda like a bike tire), except, this will obviously be awkward due to the size. I don't recommend a pool, since the pool normally has chlorine in it and there is no telling what the chemicals will do to the air mattress materials. Patch kits work well, but so does duct tape. You'll be putting a sheet or sleeping bag over it, so aesthetics shouldn't really be much of a concern. Just make sure either one you use, will be secure enough and smooth enough once it's ready to go. There's nothing like having something poke your bum in the middle of the night, or something sticking to it (I'm referring to the tape/patch).