Holbox island is easily to reach from Cancun (airport or downtown)by bus or taxi.
 
BUS: Leave from the central bus station in Cancun, located at Avenida Tulum. There are various daily connections, the service is efficient and has air conditioning. Paying about 60 pesos the bus takes you to the harbor of Chiquilá in 3.5 hours.

TAXI: Arrive Chiquilá leaving also directly from the airport, but cost like 700 Pesos. If you are a group of persons you can use collective taxis that charge more convenient prices.

BOATS: Leaving from the harbor of Chiquilá, a ferry service with hourly connections between 5 a.m. and 7 p.m., connecting the island with the main land, crossing the lagoon in about 40 minutes. The ticket costs about 40 pesos per person.

There is also a  night transportation service provided by locals, however the prices have to be negotiated at the time. The camp ground is in 10 min. walking distance from the pier. You can also reach it by taxi at the cost of 10 pesos per person.