What to do for 8 hours in Panama?

It is possible, and there are no exit/entry fees, but you will have taxi fares -- from $15 to $25 each way, depending on the driver. If you arrive at 11am, by the time you get through customs and get your bags, you won't be on the sidewalk until almost noon. Then it's 30 minutes to the city, and 30 minutes back. But then maybe add 30 minutes, because you'll be going back to the airport at rush hour. Plus, most airlines tell you to check in 2 hours early (though at Panama 1 hour is usually fine). So, that leaves you with a net of only 3 or 4 hours for touristing. Yeah, you could make a quick hop up to Miraflores Locks to see the canal and museum, or do a quick walking tour of Casco Viejo -- some good museums there. Best to line up a driver/guide in advance, I think, to pick you up at the airport, shepherd you around, and make sure you get back to PTY on time...

Depending on your citizenship, you may have to buy a tourist card (required for Canadians, for example) but it is only $5.

I agree that a trip to the Miraflores locks would be worthwhile. Certainly better than staying at the airport.

Good point: Unless they're residents of Panama, they'll have to buy the $5 tourist card to get through customs at Tocumen. In fact, some airlines make you buy it before you board, even if you don't plan to stay in Panama...

Tourist card depends on which country your from. Some countries have an agreement that waives the card. I'm from the UK and didn't have to pay. Also Tocumen immigration can be very slow and disorganized, I waited 2 hours to get through last December.

Right, sorry -- I was thinking and typing like a typically egocentric Yank. :-) There are a couple dozen countries from which passport holders require no tourist card and no visa to enter Panamá.

Btw, immigration at Tocumen has improved vastly in the past six months: They installed more booths, hired more agents, and have a new electronic queuing system. Not to say there couldn't be delays, but my last three entries were accomplished in less than 15 minutes. (Baggage claim can easily add another 15-30 minutes, however.)