The short answer, is: No.

The long answer is, it kind of depends. For the most part, US dollars are widely accepted in Cozumel, especially at the resort and in touristy areas. Tipping is often done in US dollars as well. However, there are a few situations where having some Mexican Pesos on hand can be useful.

Why Might I Want Pesos?

Special Purchases

If you plan to make a retail purchase at a local business, having pesos can get you a better price. Some businesses may offer a discount for paying in cash, and using pesos can help you avoid unfavorable exchange rates or fees that may be applied when paying with US dollars or credit cards.

Some goods in Mexico are worth shopping for locally and bringing back to the US. Some such things include fine leather goods, silver jewelry, and artisan crafts. These items are often less expensive when purchased in Mexico, and you may be able to find unique items that are not available in the US at all.

Convenience

• It can be a convenience for small purchases, such as snacks or souvenirs, where the total cost may be less than a dollar.
• Pricing is often listed in pesos, so having some on hand can make it easier to understand the cost of items. Think restaurant menus, market stalls, etc.
• It can make things less confusing at check out when their Point of Sale system calculates the total in pesos.

How Should I Acquire Them?

You can exchange US dollars for Mexican Pesos at banks, currency exchange offices, or at the airport, but these will always be a worse rate than using ATMs. ATMs in Mexico typically offer competitive exchange rates and lower fees compared to currency exchange offices. Use only large and familiar bank names like HSBC, Santander, Banamex (part of Citibank) and others are part of interbank networks you already know, like Cirrus and Plus ATM consortiums. Just look for the familiar logos.