I've a Garmin Nuvi and I'm going to travel (and drive) abroad.

Is it possible to take my Garmin with me and install a cart of the country I'm going to visit without losing the Thai map already inside ?

I have a Garmin 265 bought in Australia and have added in Thailand maps on an SD card with no problems. This is the reverse of what you wish to do, however indicates it is possible to swap countries fairly easily.

It automatically selects the correct map but takes about 5 minutes to synchonise with satellites when swapping countries. You can check what maps are installed on mine, and it shows both internal and on SD card maps.

Yes you can. Just get a Garmin nuvi plug & play (unlocked) map on microSD/SD card. After inserting card into the slot, check [Tools>Settings>Map>Map Info] to select between available maps. You won't loose the Thai map installed in the nuvi internal memory.

Yes, Garmins can handle a limited number of maps at any time. I have three county wide and a global map on my XT system. Just a matter of naming the files accordingly.

And if you have more IMG map files than the unit can allow, several IMG files can be combined into a single IMG using a utility called GMapTool.

And if you have more IMG map files than the unit can allow, several IMG files can be combined into a single IMG using a utility called GMapTool.

Most people would rather just plug in a microSD/SD card with another map into the slot. There is no need to mess with internal memory or third-party software to manipulate IMG files.

Sorry for not being clear. I was actually replying to Digitalbanana who is using Garmin Mobile XT (in data card). Since the navigation software runs off the data card, it's not possible to swap the card with a Garmin map data card. The only way to install maps is to copy maps into GMXT's data card. And GMapTool will come in handy when there are more than 3 IMG map files to install.

I missed the discussion switch from Garmin Nuvi to Garmin Mobile, not the same product or software.