Can I get pregnant if I was wearing a bikini and my boyfriend put his penis a little inside me while on the ocean? He never came.

Probably not, but... there's always a small possibility even if he says he didn't come. If you are not wanting to get pregnant yet I would recommend discussing birth control with your physician just in case!
Probaby not... The chances of a living sperm somehow getting to the right place is....well, very unlikely. unless there was more to it? Better to use protection when on dry land.
Not likely. Although pre-ejaculate can contain sperm, the liklihood of getting pregnant through a bathing suit, in the ocean, without ejaculation, is very unlikely.