This was our favorite meal in Tulum.
It wasn't by a landslide, because we had really good, really impressive dinners all eight nights. Hartwood is truly remarkable and not to be missed.
Get there early like everyone says. (5:15 to line up for the 6pm opening.) One night we showed up at 7pm and they were booked solid through closing time.
My most memorable octopus dishes to date were consumed in Santorini, Greece and at Prezza in Boston's North End. Hartwood's Pulpo Platter makes my top three. Life changing. (Sort of like the sand and the cenotes.)
So in Tulum:
1) snorkel Dos Ojos
2) fully embrace the sand
3) eat grilled octopus at Hartwood
I would also highly recommend the amberjack ceviche, the costillos al agave (pork ribs with a sticky agave bbq sauce, which are their house specialty), the sweet corn ice cream and the coffee mezcal.