I've been to ST. Thomas MANY times, and there will not be car seats available in the taxis. You might be able to wait for a regular car taxi, which will have seat belts for you to secure a car seat. As the previous posted mentioned, most of the taxis in the USVI are open air and aren't very safe, especially for children. The are very curvy and steep. If you really want to go to Magen's Bay, I'd recommend renting a car for a child that little. You'll feel better. Just a note, they drive on the left side of the road on St. Thomas. I wanted you to know, so you'd be prepared and willing to drive on the other side!!!! There are various speed limits on St. Thomas, depending on where you are. For instance, I travel to St. John most of the time. There is a posted speed limit of 20 mph for all the roads not in the main town, and 15mph in the main town. The roads are VERY open and not crowded at all. Most people are going MUCH faster than 20mph, unless you're going around a turn. I guess what I'm trying to say, is there are posted speed limits, but most of the taxi drivers and everyone else for that matter, don't adhere to them. Driving in the USVI can be VERY interesting to say the least!!!!