Yes.Its being done. And unfortunatelly it's a pretty scary answer: All you need it's the phone number . It's the SS7 protocol has been exploited since 2014 and remains vulnerable to this date.
Basically SS7 (Signaling System 7) it's a 70's protocol which lets telcos operate globally. It's used to signal on which cell tower a mobile station (with a given phone number) it's connected.
So , if you are in Hawai and someone from the US calls you, his telco would use SS7 to ask where your number is (even on which specific Cell ID). Then, when it gets all the routing data needed to communicate with Hawai's network, with the basestation you are connected with, it proceds to connect and diverges your traffic there.
But , as it was designed on the 70s, it wasn't done with security in mind. Unfortunately , SS7 doesn't require authentication in any stage of it's communications. Instead, its a trust-based system, telcos relies on each others. In other words, if you access the SS7 network, then you are a trusted source.
So , all your adversary needs is an access to the SS7 network, a Global Title (similar to a IP) with roaming license, which can be bought from a legit source such as a telco (or from a not so legit one from the deepweb).
Then the attacker sends fake SS7 messages to the network, registering your mobile station to it's own controlled basestation. Once he did this, he MiTM you, logging all your traffic and re-sending it afterwards.
Best part of this ? We can do nothing to protect ourselves. The SS7 protocol won't be modified soon , 'cause all the economic impact it would have on the operating networks. It would require that all telcos upgrades at the same time, so communications aren't interrupted.
EDIT : forgot to mention. This could be exploited from any part of the world. No need to be close to the target.