Another alternative if you just "have to have the internet" while in port, instead of wandering around looking for free or cheap wifi locations I recently purchased a International Hotspot device called SkyRoam, (NOT shilling for the company here!) It's a cellular hot spot device that works in over 140 countries on their cellular data networks and it doesn't require you to sign up for any plans or data packages or buy sim cards etc. You just turn on the device and once it finds the data network in that country you can activate your day pass (bought in bundles of 5 or 10 day passes for about $8 a day) and off you go, it's good for 24 hours of unlimited DATA on the cellular data network in that country. Heck if you move to another country port with in that 24 hour period you can still use it for that same day pass until the 24 hours expire. I took it on the recent Westbound Panama Canal cruise from Port Canaveral to San Diego and it worked great in every port we went to, Cozumel, Cartagena, even through the Panama Canal, Puerto Vallarta and Cabo San Lucas with no problems. The device worked whether I went ashore in port or while I remained on the ship. It's a great alternative to dealing with your cell provider over which service will work and having to sign up and stop the service when your trip is over. I know there were 3 or 4 other cruises on the WBPC trip that also had the same device and we all experienced no problems using them. There's no monthly fee, no activation costs just buy it, and the day passes, once your day pass expires there's no additional cost until you activate another day pass. This is just my experience and I wanted to offer it as a alternative, especially for active cruisers or travelers.
