What Camera are you using?
If it's a camera which uses an SD card, why not just purchase more cards?
What mode (Raw, JPEG Medium, JPEG fine) are you shooting?
What's the file size?
How do you plan upload them? Laptop, iPhone, iPad?
Do you know that you will have adequate wireless support overseas to do the uploads?
In Africa I wasn't able to use camera control apps for my Canon cameras as they required internet access for activation. There was internet access, but it was so slow that the application didn't even recognize the internet was there.
In Vietnam they had terrific internet speeds (50 Mbps or better) in almost every hotel. However there had been a typhoon which broke the outgoing international cable, so international connections were extremely slow.
Hotels may not offer internet access in your room, but may require you to go to the lobby. Or you may have to pay a daily fee (which may be prohibitively expensive) for access that is still slow.
For critical photos you can't assume that you will always be able to upload. Carrying more SD cards or an external hard disk for backup of critical files might be an option.