There are crocs in the lagoon, but difficult to spot normally. There are a few restaurants with lagoon frontage that have a resident croc lurking nearby waiting for scraps.
1 block up the road to Pok to Pok Dumpy hotel on the left-Royal something(it's a shithole). Bar & Dock out back-there is a croc that suns pretty much all day every day on the dock.
Captian's Cove has a big Croc Hangs out next to the outside tables of the restaurant. It is located on the Lagoon side accross from The Royal Resorts
There's one that hangs out near the Black Pearl on the lagoon, catch him at the right time (early evening usually). I really recommend going to the Crococun Zoo as well, a hands on environment where you can hold a baby croc, lizards, snakes, feed the deer and monkeys,etc.. Its' a small place, the tour only takes about an hour, but well worth it. Walking through the adult croc enclosure makes your heart beat a bit faster! We saw a BIG croc in a lagoon near Petempich, but might not be worth the drive if you don't get lucky.
head down the slide at senor frogs in back, it shoots you into the lagoon, get a few crocks to nibble on your feet!! Kidding its roped off but it makes you wonder hahaha