In Belize we were thankful that we had booked an excursion previously. This is NOT a port that you would want to walk freely through the streets. It is an extremely poor area and crime ridden.
With that said, we booked a tour that came highly regarded from a friend through http://www.cave-tubing.com. My husband, friends, and I booked the zip-lining and cave tubing excursion for $75/per person US. We were SO happy with our tour guide and the company as a whole! They picked us up at the port and our guide was holding a sign with our name on it. We (along with two other families) boarded a van and we were taken on a 45 minute ride to get to the site for the zip-ling and cave tubing.
We zip-lined first and what an experience! There are 7 separate platforms. The first one is a simple "chicken run" as they called it. From there they get higher, longer, and faster! It was so much fun and we were able to take photos and videos while we zip-lined.
Next we went to the cave for the tubing portion. What a beauty of nature. You go on a tube with headlamps and you can see the stalagtites, stalagmites, and different rock formations within the cave. There is a waterfall inside as well, and you can also see the glittering quartz veins on the cave walls. Truly a mesmerizing experience! We then just sat in our tubes down the river for another 25 minutes and throughout the experience our guide was telling us about each rock, tree, leaf, and the local culture.
Once the tour was complete, we were brought back to their tropical "hut" and were fed chicken tamales. YUM! Some of the best I have had. After eating we were able to change out of our wet clothes and then took the 45 minute ride back to the ship port. (PS: We were able to lock our things in the van while we did the excursion. The zip-lining and cave tubing is in a national park there and there are ARMED guards so it is very secure).