Using do not disturb function overseas

I have set up my overseas minutes with my network provider.

i just wanted to know if when I go abroad and put my iPhone in do not disturb, will it go straight to my voicemail without the other person knowing? Just like in the UK? Or will it have an international ring tone before going to voicemail? In which case the caller will know I’m abroad.

just want to clarify what the other person will hear when I go abroad and my iPhone is on night mode.