For android, the answer is yes (without rooting being required).
> without rooting being required
If you want to use the standard port, that's only true as of very recently, though, see https://issuetracker.google.com/issues/218578943#comment17
Also on iOS, though I've only done this over Wi-Fi, and have no idea whether telcos expose open ports to the (IPv6) Internet.
> without rooting being required
If you want to use the standard port, that's only true as of very recently, though, see https://issuetracker.google.com/issues/218578943#comment17