Built by De Havilland Canada from 1965 to 1988, Viking Air purchased the type certificate and restarted production in 2008, before re-adopting the DHC name in 2022.

The availability of the 550 shaft horsepower (410 kW) Pratt & Whitney Canada PT6A-20 turboprop in the early 1960s made the concept of a twin feasible.

[7][8] After Series 300 production ended, the remaining tooling was purchased by Viking Air of Victoria, British Columbia, which manufactures replacement parts for out-of-production de Havilland Canada aircraft.

On 24 February 2006, Viking purchased the type certificates from Bombardier Aviation for all out-of-production de Havilland Canada aircraft (DHC-1 through DHC-7).

On 2 April 2007, Viking announced that with 27 orders and options in hand, it was restarting production of the Twin Otter, equipped with more powerful Pratt & Whitney Canada PT6A-34 engines.

[20] In June 2023 Viking, now operating as De Havilland Canada started production of new DHC-6 Classic 300-G.[8] Twin Otters could be delivered directly from the factory with floats, skis, or tricycle landing gear fittings, making them adaptable bush planes for remote and northern areas.

Many Twin Otters still serve in the Arctic and subarctic, but they can also be found in Africa, Australia, Asia, Antarctica, and other regions where bush planes are the optimum means of travel.

In Norway, the Twin Otter paved the way for the network of short-field airports, connecting rural areas with larger towns.

During one period of its tenure in Norway, the Twin Otter fleet achieved over 96,000 cycles (take-off, flight, and landing) per year.

According to the February 1976 edition of the Official Airline Guide, Houston Metro operated 22 round-trip flights every weekday at this time between Clear Lake City (CLC) and Houston Intercontinental Airport, now George Bush Intercontinental Airport, in a scheduled passenger airline shuttle operation.

The Walt Disney World resort in Florida was also served with scheduled airline flights operated with Twin Otter aircraft.

Another commuter airline in the United States, Rocky Mountain Airways, operated Twin Otters from the Lake County Airport in Leadville, Colorado.

At an elevation of 3,026 m (9,927 ft) above mean sea level, this airport is the highest airfield in the United States ever to have received scheduled passenger airline service, thus demonstrating the wide-ranging flight capabilities of the Twin Otter.

Rocky Mountain Airways went on to become the worldwide launch customer for the larger, four-engine de Havilland Canada Dash 7 STOL turboprop, but continued to operate the Twin Otter, as well.

[23][24] In many cases, the excellent operating economics of the Twin Otter allowed airlines large and small to provide scheduled passenger flights to communities that most likely would otherwise never have received air service.

[26][27][28][29] On 21–22 June 2016, Kenn Borek Air's Twin Otters performed the third winter evacuation flight to Amundsen–Scott South Pole Station to remove two people for medical reasons.

The Twin Otter is also used for landing at Juancho E. Yrausquin Airport, the world's shortest commercial runway, on the Caribbean island of Saba, Netherlands Antilles.

[39][40] Two days later, the aircraft departed Victoria, British Columbia for a ferry flight to Orlando, Florida, site of the 2008 National Business Aviation Association (NBAA) Conference and exhibition.

[41] Transport Canada presented Viking Air Limited with an amended DHC-6 Type Certificate including the Series 400 on 21 July 2010.