I retired in February. I have a little over a decade in with Federal agencies (DEA, DHS, etc.) and many other jobs when younger. You may want to add Panama to your list since you're considering Costa Rica and Belize. It has excellent healthcare (U.S. affiliated hospitals) and a reasonable cost of living in many areas. As someone else stated, Costa Rica has become more expensive and has started to experience drug-related crime issues. I'm not saying don't retire there, I'm saying just be aware that they are experiencing these issues.
Latin America is a bit of a mess right now. For instance, Ecuador, which was very recently an excellent choice for retirement due to the tranquility of the country and very low cost of living, has completely imploded. I love the vibe of Colombia where I have traveled extensively over the years, but it has it's own set of issues. A DEA agent was murdered (on video) when two robbers jumped into the backseat of his taxi right after he got in. He made his way out of the taxi but ended up dying in the street from stab wounds. If it can happen to a physically fit, highly trained DEA agent, it can happen to anyone. That was years ago but is a risk that still applies today IMO. Medellin, which is a great city, has recently been experiencing a string of murders of Americans and has been plagued with an insane number of druggings/robberies. Some of those druggings have resulted in fatalities when too much of the drug was used.
I guess Belize could be considered because of English being their primary language but it is substantially less-developed than Panama or Costa Rica. And I believe you get much better healthcare in those countries than Belize. Mexico is great for proximity to the U.S., but comes with with its own set of well-known issues.
Someone mentioned Pattaya, Thailand. I have been there and Bangkok also. In my brief time in Pattaya I found it to have a bit of a rough edge. I noticed a lot of Russians and Pakistanis or Indians (not sure which). Some of the Pakistanis/Indians were extremely rude in sexually lurid ways to my female companion just walking down the street. I almost beat the crap out of one guy but she talked me down and rightfully convinced me that we didn't want to ruin the night dealing with Thai law enforcement. Still, it was disturbing that they felt free to act in such a manner. I also observed a lot of shady looking Russian guys. Some seemed like Russian mafia types. She confirmed that is an issue there. But Pattya is a decent size city with a lot to do, near the water. I wouldn't cross it off the list but be aware that of what I encountered in the bar/nightlife area of town.
I didn't see any of those issues in Bangkok. But it has its own problems because it is simply massive. Traffic is possibly the worst of any city in the world. There are many other areas of Thailand I didn't have a chance to go to that I understand can be outstanding places to retire. Chang Mai, Hua Hin, etc. it kind of depends what type of lifestyle you're looking for.
In virtually all of these countries that I and others have mentioned in this thread, usually the big cities and tourist towns tend to be more expensive and the costs of living can be substantially lower as you move out to more rural areas. So the cost of living can vary wildly within each of the countries.
I will be moving overseas to live out my retirement. I am considering Panama, Costa Rica, Mexico, Thailand, and Philippines. I may add Portugal and Spain to my list since I have a friend who will be retiring in Portugal. Those countries tend to have a higher standard of living and are quite a bit safer than the ones I am currently considering. I'm willing to take on a bit more risk for more disposable income since I am single.
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