Season five of Nine's maritime drama will be its last.
The decision to wrap up Sea Patrol is due to financial assistance ending for production under a government tax rebate.
The rebate was available to producers McElroy All Media for 65 episodes, but next year the series reaches 68 episodes.
With its mammoth locations and logistics, Sea Patrol is at the high end of production costs.
The fifth series will clock in at 13 episodes, three less than in 2010, with the return of cast members including Lisa McCune, Ian Stenlake, Conrad Coleby, John Batchelor, Matt Holmes, Kristian Schmid, Nikolai Nikolaeff, Danielle Horvat and Tammy McIntosh.
Sea Patrol began in 2007, the same year as City Homicide, with a mix of action and romance on the high seas. Its border patrol plotlines have capitalised on interest in topical themes while delivering broad stories for a mainstream audience. It has aired globally via the Hallmark Channel.
Last season it averaged over 1.2 million viewers per episode, which is considered a good figure in today's multi-channel environment.
Where this leaves Nine's future drama output in meeting local quotas is unclear.
So far in 2011 Underbelly may be made into three telemovies, Rescue: Special Ops has been renewed for an increased 22 episodes, while Cops L.A.C. is under-performing so much it could well be on its way out.
Last week Seven announced it was undecided if it would renew City Homicide for a fifth season. At this stage six new episodes will air in 2011.
Executive producer, Di McElroy, said: "Our cast and crew love the thrills, spills and very real danger of shooting on a warship on the high seas."
Executive producer, Hal McElroy, agreed: "We're determined to make this our best season yet."
Filming concludes in February.