Coba was the first set of ruins we set out to see during our 10 day trip to the Yucatan. Judging by the number of cars in the lot, we were among the first visitors to the site that day (9:00 am). We paid our fee and entered the site. Within the first 100 meters, you see the first set of ruins off to the right (Coba Group) and a parking lot of around 500 bikes on the left. Because the site is so large and spread out, they allow you to rent bikes to go exploring on. Since we enjoy hiking and observing wildlife, we opted to just walk.
We had only made it to the 2nd set of ruins (Paintings Group) before a 'river' of bicyclists came roaring by on their way to Nohoch Mul, the large temple you can climb, indicating the first tour bus had arrived. This was just the beginning, every 5 minutes or so, a group of 20-40 bicycles would emerge from down the path either coming or going from Nohoch Mul. By the time we arrived ourselves, the temple was covered in people ascending or descending the grand structure. Even so, it was hard not to stand in awe at the shear size of it. Like everyone else, we made our way up the steep stairs and enjoyed the commanding views the temple offered of the surrounding landscape.
Aside from the great temple, there are many detailed stela and other features spread throughout the site worth a few minutes of your time. The rest of the building groups are not quite as 'busy' as the main temple, so you can enjoy them at a little more relaxed pace.
Interesting enough, if you read reviews by other posters, they all give a 'shout out' to the tour group they used to get there. I think that speaks volumes to the number of people that go through the site each day. Sure, it probably isn't as visited as either Tulum or Chichen Itza, but rest assured it is right up there!
While at the time, we didn't realize how distracting the crowds were, in reflection they really were an annoying feature of the site. Especially since as we continued our journey, we would end visiting the site of Becan as the only tourists during the 2 hour period we were there.
Crowds aside, if you aren't able to get to some of the more remote sites on the peninsula, Coba does offer a unique experience you can't get from either Tulum or Chichen Itza by allowing you to climb and explore the ruins. This alone allows a perspective you just can't get by observing strictly from the ground.
I believe the site opens at either 7 or 8 am, the early you can get there the better. Had we arrived even just 15 minutes earlier, I think we could have enjoyed Nohoch Mul in relative peace. As it is, the buses/tour cars start arriving shortly after 9:00 and continue to roll in all day.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.