"Seeing our young athletes succeed is why I love my job, but equally I love the opportunity it presents to take swimming to our wider community - to increase the safety of our young people in the water and build their self confidence."
Johnson started out as an outstanding swimmer in his own right, winning world titles and medals at the Deaflympics and is still the holder of a number of British Open deaf records nearly 30 years on.
He coached legendary British Paralympian Sarah Storey, who won 11 Paralympic gold medals in both cycling and swimming, to two of her gold medals in Barcelona in 1992.
He also coached British multiple gold medallists James Hickman and James Goddard in their formative age-group years, and was the Scottish Youth Coach of the Year in 2003.
High Performance Swimming New Zealand development coach Donna Bouzaid said Johnson was a great asset.
"Alastair is one of the best coaches I have worked with. I value him as a colleague and a friend. It is great to see what he is already achieving in Rotorua and I can see heaps of potential for the future."
After working at the AquaGym Swim Club in Christchurch, Johnson and his family returned to the United Kingdom in 2009. A few years later, they moved to Rotorua.