Not true, keep your passport and tourist visa locked in your room safe (if you want to carry a copy

My husband and I are traveling to Mexico for the first time and will be staying at Dreams Tulum for a week. I keep reading you must have your passport and tourist card with you at all times. We plan to do a snorkling excursion and a day at explor possibly. I was wondering how do we keep these documents safe ?
Do we need to take them with us? I would hate to lose either. I was thinking of making a copy of my passport and laminating it and carrying my drivers gps airline flight tracker license. I would then lock the original in my safe.
Not true, keep your passport and tourist visa locked in your room safe (if you want to carry a copy you can) as the only time you will need this other than at the airport, is if you want to exchange money at either a bank, casa del cambio or the front desk of your hotel. Due to limitations on how much money each tourist can cash, these places must track your passport. If using an ATM, no problem here. And yes, do exchange dollars for pesos, your money will go much further.
I take my drivers license gps airline flight tracker as photo ID (not that anyone asks, but just so I'm not walking around alone in a foreign country with no ID on me). I also have an "in case of emergency" card I made up giving name phone number of a couple family members).
Sometimes I do keep some money and a copy of my passport (1st two pages w/the identifying info)and the car keys and other valuables on me at the beach while traveling and snorkeling in other countries. I have also kept my passport on me when I get off of a cruise ship and go on a beach excursion.
When I do that I use one of these, see below, a Splash Caddy waterproof wallet gps airline flight tracker belt. It works well for me and it is very waterproof. I have never had anything get wet in it. I double bag my items, inside one splash caddy bag then that bag inside another splash caddy bag.