The 2011 off-season is longer than usual (March–October) as Football Federation Australia shifted the next season's start back to avoid clashing with the NRL and AFL finals.

Whilst in Canberra, the Mariners retained the Bank of Queensland Cup, winning their annual clash with Belconnen United FC 5–0.

Overall, the Mariners enjoyed a successful pre-season, including wins over A-League opposition Perth Glory and Wellington Phoenix.

This included a draw with Gold Coast United, thanks to a late Patrick Zwaanswijk equaliser, and a loss in The F3 Derby against Newcastle.

Late in the month, it was announced that local long-serving striker Matt Simon would be leaving in early January to play for K-League side Chunnam Dragons.

Matt Simon left the club to go to South Korea, scoring a brace in his final game before moving overseas against Melbourne Victory.

Mitchell Duke, Jimmy Oates and Anthony Caceres were promoted from the youth team under the terms of their "senior" contracts for the 2012 AFC Champions League and future A-League seasons.

On 31 January the Central Coast Mariners confirmed that they had secured the services of John Sutton for 4 months on a loan deal to cover the loss of Matt Simon.

February saw the end of the Mariners' extended undefeated run, and two other losses in the month saw the lead at the top of the table reduced ahead of Brisbane Roar.

Wins in the last two games of the regular season earned the Mariners the 2011–12 A-League Premiership, ahead of Brisbane Roar.

A 5–1 win over Tianjin Teda FC- the club's first in the AFC Champions League- saw the Mariners travel to Japan needing to beat Nagoya Grampus to progress in the competition.

In December 2011, they were drawn in group G, along with Nagoya Grampus of Japan, Tianjin Teda FC of China and Seongnam Ilhwa Chunma of South Korea.