There are practically no cars on the island. I remember seeing a police pick up, parked in the middle of the street, missing the front left wheel. For the transportation most people use golf carts or they ride a bicycle.
When we talked to an older local man about how Holbox has managed to remain so pure and untouched, he said sadly: 'For the locals Holbox is a rare diamond. I hope 'they' will not destroy Holbox the way they did with Isla Mujeres ...'
The one thing Holbox is very popular about is swimming with the whale sharks. We missed the season though, since we came there in March. The best time to swim with them is from June to mid-September.
The southwestern part of Holbox is an ecological preserve and much of the island is a wild mangrove forest.
There are pretty much other things you can do on Holbox. The island is about 26 miles (42 km) long, so you can go on a tour around the island with a golf cart or a bicycle, see some other small islands near by or you can just relax and enjoy the amazing beach and snorkle in the sea.
Useful hint: Before you arrive to Holbox, make sure you have enough cash. There's only one ATM machine. The day we arrived there, we wanted to withdraw the money and in that moment the ATM machine stopped working. Nevertheless, we found this pretty funny, well at least until we became so hungry, we would have started eating a wooden table if we had to. We went back to the boutique, where we bought some small gifts and a nice lady told us that a cashier at the grocery store probably could take our credit card if we buy something and return to us the rest of the amount in cash. So, we tried that too, but no luck. At the end we managed to get our money from bakery for a small fee (5%). We used a credit card for a couple of hundred bucks and the cashier gave us the cash.