One way to think about "transporting / transporting" Bitcoins is to understand that they are not at all with you. You can imagine the Bitcoin blockchain as a giant safe with infinite boxes.
The "Bitcoin" that you carry is actually the key to your box in the safe.
So, let's rephrase the question:
Can you take information from one country to another?
Legally speaking: if you do not go to a dictatorship, yes.
Concretely, nobody can know what you carry in your mind.
Do you need to carry a wallet (a hardware or software component that stores this information for you) in another country?
You may want to do this discreetly to avoid problems or abuse with customs officers or even be robbed during a trip.