This is the second expansion set for Bohnanza and it can be played either with or without the earlier expansion, though if you don't have the earlier one, that "2-7 players" comes down to "2-5". It consists of two more sets of bean cards, together with some ships and some harbours and the aim seems to be to add some extra tactical complications to the basic game.
At the start, in addition to the usual two fields and some bean cards, each player has a harbour and a merchant ship. There is also, in the centre of the table, La Isla Bohnita itself, with its two harbours, each containing a row of bean cards. The ships function as floating warehouses and can pick up beans either from the player's own fields or from the central island. However, there are a couple of major restrictions to the freedom of action that this seems to open up: the ship can only carry one type of bean at a time and it can't offload its cargo until it can be sold for at least one taler. All the loading and offloading takes place during what in the basic game is the trading phase.
Players still have the option of purchasing a third field and now they can also purchase a second merchant ship and a pirate ship. Pirate ships steal beans from merchant ships, but since they are also subject to the rule about having only one type of bean on board, their activities don't get out of hand.
And there you have it, a bit of extra tactical chrome for one of last year's hits. And as soon as I use the word "chrome" I start to reveal my opinion, because, like most of my race, I associate chrome with unnecessary decoration and that is what this is. The joy of the original was in the chat and the deals as you tried to get your hand into profitable shape. This expansion adds nothing to that. Instead it just gives you some fiddly rules to think about and a lot more time to spend watching other people do things that don't interest you. The publishers estimate the playing time of the original game at 45 minutes; they have this one at double that. The extra time is not well spent. This is not an expansion that you need and the only qualification I would add to that is "unless you want to try Bohnanza as a 2-player game". The rules contain a 2-player variant that you can play using the extra pieces. I haven't tried it and so don't know how well it plays. Bohnanza as a 2-player game doesn't appeal to me, but it may well to you, and if it does La Isla Bohnita means that now you can play it.