In early 1969, Tamgass Airways company founder and pilot Pete Johnson made the decision to rename the air taxi to Alaska Southcoast Airways to better promote regional level service, while still operating under the Tamgass Aviation, Inc. certificate. A new larger Southcoast terminal building was constructed between the big U.S. Coast Guard hangar and adjacent Federal Aviation Administration control tower, with aircraft fuel pumps and parking ramp space for the expanded amphibian fleet. Most of the outfit's newly acquired planes carried civil registration N-number series ending with the letters "SC" for Southcoast, and wore bright red orange high visibility color scheme trim on overall white to stand out. To advertise their official affiliation as a certified member of the National Air Taxi Service Association, Southcoast sported that organization's distinctive Kangaroo logo on each plane and using their "Kangaroo Commuter" slogan in 1969 display ads. Johnson and partner Mark Murdock hired on more pilots for the busy season. Pete and Mark continued to do most of their required routine scheduled maintenance during the evenings, which was still being carried out at the original Tamgass Airways hangar location just to the north off the main runway. U.S. Coast Guard Air Station mechanics like Bob Luse, often moonlighted to help keep pace with the job of keeping Southcoast's busy birds airworthy.

Offering connections with Boeing jet travelers continued to be a primary part of Southcoast's business, since Tamgass' early 1964 start, meeting up with Pan American, Pacific Northern, Western, and finally Alaska Airlines. A twin-engine Cessna 310 wheelplane (N984SC) was added in May 1969, for faster (200 mph) long range airport-to-airport charter commute between Annette Airport and Juneau, Sitka, Petersburg, Wrangell, and even Seattle destinations. The one way Annette to Seattle ticket fee back then was $100.00 per person, when four passengers were booked. International connecting flight service to Prince Rupert, BC, Canada was also frequently logged. At some point in time, Southcoast discontinued using Nordby's Supply dock by City Float as the company's Ketchikan downtown seaplane terminal, and relocated over to the adjacent 509 Water Street office and dock property, where Stan Oaksmith, Jr.'s original Ketchikan Air Service (1943-1953) once operated (the current address of the Artic Bar). The competition between local rival scheduled and on demand charter air companies operating amphibian seaplanes that included service over to Annette Airport grew more intense over time. Alaska Coastal - Ellis Airlines' mighty fleet of large capacity nine passenger Grumman Gooses and 24 passenger PBYs ran daily scheduled shuttle flights to Annette Airport, that continued following the 1968 merger with Alaska Airlines. Webber Air and Coast Air Gooses also joined in the mix whenever booked to meet demand.

In 1970, Mark Murdock decided to leave the company to take on a new job with El Paso Natural Gas and Petroleum as a corporate pilot assigned to take delivery and fly their new Helio Courier amphibian seaplane (N6471V) to be based in Ketchikan for their Southeast Alaska mineral exploration operations. With Ketchikan's new international airport on Gravina Island opening August 1973, the inauguration of the Alaska State Ferry's four days per week schedule from Ketchikan to Metlakatla the following summer, and the U.S. Coast Guard Air Station's announcement of plans to relocate to Sitka by 1977, the writing was on the wall. Pete Johnson was finally forced to make the tough inevitable decision to shut down Alaska Southcoast Airways, which subsequently went out of business June 1, 1976. He sold his Tamgass Aviation, Inc. operating certificate to Metlakatla resident flyer Jerry Scudero to start up his new Annette Island based company Taquan Air Service, Inc., using a single amphibian Cessna 185.

Aircraft:
Cessna 180/185 Skywagon, Cessna 206 Stationair and 310 wheelplane, and DHC-2 Beaver amphibian seaplanes.

Pilots:
Pete Johnson, Mark Murdock, Cal Tassainer, Jerry Taylor, Jon Gilson, Gene Krattli, and Jim Duppenthaler, among others.

Mechanics:
Bob Luse and Don Mills, among others.