San Luis beach, the one located across the road from the Decameron San Luis, is a small but nice public beach. It is flat and has shallow waters, but it can be a bit windy and have small waves. be careful when it is choppy, as there's a bit of undertown
This beach is not very crowded but you can feel the Decameron influence there, as it's possibly the only beach (except for the one in El Centro) that has quite a few people walking about selling things. Do wear your coral shoes there, as you may occasionally step onto some small sharp rocks.
San Andrès town beach is a continuous row of independent beaches which are quite plesant to spend your day there and have dazzling white sand. Normally they are not too crowded and the sea right in front of them has a lovely emerald colour.
The best stretch of beach is past the casablanca hotel, where it is quiter and the sand strip is larger. it's possible to rent chairs (carpas) and sorts of tents to protect yourself from the scorching sun. In July 2008 the price was about 10000 COP.
Touring around the island in a rented golf cart seemed like the thing to do while we were there. Our group decided against it however because there was no insurance available, and if something had happened we didn't have money to pay for damages. That said, we are possibly just not big enough risk takers because tons of people seemed to be able to do it without incident. It's a great way to see the island, you just need to watch out for other motorists. I'm not sure I would reccommend doing this from one of the hotels in town or not because traffic seemed quite heavy at times there.
It was very easy to catch a bus into town to do some shopping. The shops in town though are very traditional and there was a lot of stuff that we could have gotten at home. There was however the occaisional shop that offered handicrafts or necklaces and other little trinkets. There were also a some lagre duty-free shops for anyone interested in that.
Watch out for mopeds and scooters!!
The Blow-Hole is the only natural attraction on the island other than the beaches or scenery. It's located at the Southern tip of the island, and is exactly what is sounds like... when the ocean is a little bit rough, you can go and watch as the water goes through a cavern and shoots up into the air, much like a geyser.
We went on a day that was very calm though, so unfortunatly is was just a hole in the ground that day we went, not so spectacular. The rest of the week was very choppy though so it would have been blowing then.
We booked this tour through our hotel. It was a 3 hour guided bus tour of the whole island. It stopped about 6 times at various spots around the island, including the blow-hole, Morgan's Cave, the first Baptist Church up on the Hill, a house that was restored to be like it would have when the island was first settled, among other stops.
It was a great way to get our bearings of the island early in the trip, and only cost $20US and drinks were included!
You can hire abike, it is very cheap and you will not need more than two or three hours to go every where on the island and even hava a swim in La Piscina and go to Morgan's Cave