A trip across to Tobago from Trinidad is a must, with the completion of the country visit, but also for the relaxed and friendly feel over on the little brother island, as opposed to the hustle and bustle of Port of Spain on the bigger of the two.
Of course, you can chose to pop over and stay a couple of nights, but it is also totally manageable as a day trip.
There is a fast ferry, taking just 2.5 hours, and costs just 75TT, and there are several scheduled throughout the day from Port of Spain terminal.
The return is regular also, on every day but Wednesdays. On Wednesdays they clean the vessels, and thus the last fast ferry back to Trinidad is 12 noon.
There is an 11pm cargo vessel for which you can buy tickets for, but be warned - this is a 5 hour journey on a ship with trucks and limited passenger space. In fact, I was told there was barely cover for the passengers, and thus perhaps to be avoided. We managed to grab a very cheap flight back to Trinidad in the late afternoon, of which are scheduled at very regular intervals.
In terms of Tobago, upon arrival you will be greeted by a host of potential tour guides as you disembark from the ferry, who will show you the island at your own pace, and allow you to stop wherever you want. What more could you need!!??
The island is a forest gem, with gorgeous blue water lapping perfect white sand at every bay, which is around every other turn all the way around the island.
Great food, beautiful forest and beaches, and friendly people!