In the late 1970's when I did two Med Sea deployments if we needed to call home to the states we had two choices. One was go to the ships HAM Radio operator {limited usually to emergencies only} and get a minute or two call through HAM Operators Patching it. The other was to either go to a USO or the port cities phone company office and sit and wait up to 8 plus hours. Been there done that LOL.
Now one thing I did manage to do in 1979 in Venice, Italy I could not do anywhere else was walk into a phone booth on the street and immediately get an overseas operator.
My cousin's son was on the USS George Washington in the second Iraq War. While in the Indian Ocean or anywhere at sea he could walk into the crews lounge on ship and call home on satellite phone. It cost a good sum per minute but the ability was there.
I worked with a guy who was sent out to ships to install Ma Bell’s sat com phone systems for the Navy. That had to have been a Hell of a gig.