La Marina is the restaurant directly underneath the hotel of the same name.
The restaurant entrance faces out to the Harbour, The hotel entrance to the street at the rear.
The interior of the restaurant is simply, if not tastefully decorated, in a 'harbour-ish' style, (have a look yourself and you work it out). The wine selection is excellent, the food is very local, the quality is great, and the service good. But it is just a little expensive. Not in UK terms, but defiantly in relation to Ibiza prices generally.
So if you want to sit out and enjoy dinner as close to the harbour as you can get, pick you moments carefully, otherwise you could be treated to the noise of 6000 coke bottles being loaded on/off the Barcelona ferry.
It is one of the few places where you can buy a full meal at lunch time, and enjoy sitting outside on the harbour with a glass of wine at any time of year.