Question

Why does T-Mobile prefer AT&T roaming in Maine over US Cellular ?

  • 29 July 2022
  • 3 replies
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Userlevel 7
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Just had a trip through Maine up to Canada, and noticed something .. unusual.

T-Mobile devices  (SIM) ‘prefer’ AT&T LTE (throttled to ~256kbps) over US Cellular 5G/LTE - throttled to ~3Mbps.

While ‘service is service’, I do find it strange to have T-Mobile preferring AT&T over US Cellular.  US Cellular can still be manually selected, but by default, AT&T’s service is … less functional due to the heavy throttling.  


3 replies

While I can’t help answer your question, I have a follow up question for you. How was the service and more specifically data while you were in Canada? I’ve looked at coverage maps, but unsure how much throttling the Canadian companies will impose. 

Userlevel 7
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The GSM/3GPP system generally prefers the allowed roaming partner with the strongest signal.

Userlevel 7
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I’ve been using Canadian carriers for ~15 years.  T-Mobile speeds are good, and service is generally good (Canadians pay through the nose for service, so it’s typically under utilitized).  You’ll primarily be on Bell/Telus from my trips on T-Mobile.  Cities may pick others as well.

Rogers typically doesn’t allow for selection (you might get it in NW Ontario).

I’ve hit ~200Mbps on LTE (Samsung doesn’t have compatible n5 band on S21).

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