It started operations on January 28, 1878, as the District Telephone Company of New Haven.

Since its inception, SNET has held a monopoly on most of the telephone services in the state of Connecticut; the only remaining exceptions are the Greenwich and Byram exchanges where Verizon New York provides telephone service.

On October 24, 2014, Frontier Communications completed its purchase of AT&T's Connecticut operations, including Southern New England Telephone and SNET America, for $2 billion.

On September 5, 2024, Verizon announced that it will buy Frontier Communications for $20 billion.

The acquisition, if approved, will see Verizon taking control of Frontier’s operations, including SNET.