You have two options here. You can acquire maps before you go to the Yucatan or you can arrive there and look for a map. If you are simply going on a vacation and want to visit a ruin site or two then obviously going through the time and effort to pre-order a map may seam pointless as you can acquire a map for free once you arrive.
WHAT TO EXPECT
Most car rental agencies at resorts will not have a map. Resorts and hotels do NOT typically carry maps nor do they even sell them in their gift stores, however they sometimes carry some of the tourist booklets found at Cancun airport. If you arrive at Cancun airport this will be the best place for you to find maps [for Cancun and the Maya Riviera] unless you are staying in Playa del Carmen.
Maps to look out for at Cancun airport are:
These pamphlets/booklets are filled with coupons and advertisements but also carry maps of Cancun, Cozumel, Playa del Carmen and highway maps that can get you from Cancun to Tulum, Coba and Chichen Itza.
NOTE: The cover of these booklets will be different but the names will remain the same.
CANCUN – MAYA RIVIERA
In the Maya Riviera at every resort/hotel you will find a pamphlet called MAPA [see above]. This pamphlet has a basic map of the Riviera and is good enough to travel with. It also has a map of Playa del Carmen. There is also a book usually found in 3-5 star resorts called “Cancun Tips” which has an okay map in it of the Riviera between Cancun and Tulum.
MAPS TO PURCHASE
Riviera Maya Maps
By far the most up to date and accurate maps of the Riviera Maya are produced by a couple named Laura and Perry who make a variety of maps as an act of love. They are to be commended for their diligent work and now made them available through Amazon. You can browse the selection they offer and see that all of them have outstanding reviews.
Two other maps worth considering as and remain really great choices are the Yucatan map by Borch and the Yucatan Peninsula Adventure Map by National Geographic. We have purchased both of these and think both are very well made maps.