A friend of mine is getting posted to Diego Garcia for about 6 months. I did some checking and the communications situation there seems rather grim. The local monopoly for personal service is
Sure (formerly C&W). They provide landline, long distance, DSL, and cellular service at fairly high rates. I have not found a US cellular company that roams there and their SIMs don't appear to have any roaming. While on-island calls and texts are only 11¢/min and 4¢/ea, calls off-island are $1.05/min. From the US it costs something over $1/min to call any number on there. Data is available at the rate of 100MB/$10.
Does anyone have any other information or experience with Diego Garcia?