If you have not been in a large lava tunnel, this one is very impressive. It has good stairs in and out, it is lit, and road access is easy. There is one part where you have to crawl for about 5 ft, so expect your knees to get a little dirty. The rest of the tunnel has very tall ceilings and it is about 10 to 15 ft wide. See picture. The tunnel is about a 15 minute walk through it and your driver should move to the exit while you are in the tunnel so you do not have to back track. The tunnel is free, but there are no facilities.
This tunnel is also close to the giant tortoise reserve and the large sink holes. You can do all 3 of these attractions easily in a half day. Our driver charged us $12 per hour and there was 6 of us. If you have the time, a must do if you have not been in large lava tunnels before.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.