Travel company Carnival announced this week that it's launching a new suite of mobile games aimed at entertaining guests on its various cruise lines, either via in-person interactions (pictured) or good ol' gambling.

What's really interesting here is how these mobile casino games will work: they'll be freely available as PlayOcean Everywhere, a four-in-one mobile game (poker, roulette, bingo, and slots) that are played for fun with in-game currency -- while the player is on land.

But when the player is out in international waters -- on a Carnival cruise, for example -- a second game app, PlayOcean Casino, can be used to play the games while gambling with real money.

However, it appears as though Carnival intends for players to be aboard a Carnival ship in order to make the switch, a notable (and presumably vital) requirement given how strict and varied gambling laws can be in different places around the world. 

Carnival also plans to release a bunch of other "in-person interactive experiences" (everything from a bar crawl/poker mashup to a scavenger hunt) which can only be played aboard select cruise ships, often with the aid of a mobile device.