Patersons Stadium is on the verge of being a sellout after Fremantle crashed through the 45,000 members barrier this week - a club record even before starting their 2014 campaign against Collingwood tomorrow night.
The Dockers believe they will sell all remaining reserved seats early in the season.
West Coast has sold out its games for several seasons and has more than 52,000 members signed up of a target this year of 60,000. It had 58,000 last year.
This includes interstate and overseas members but several thousand are "In the Wings" members waiting for reserved seats at the 43,000-seat stadium.
Fremantle chief executive Steve Rosich confirmed Purple Army membership would earn priority access to seats should they become available.
Eagles In the Wings members and the Purple Army will also get priority access to seats at the new 60,000-seat Burswood Stadium when games shift there in 2018.
Fremantle's emergence as an AFL power is mostly a windfall but can have side effects. It and West Coast are among just five AFL clubs who met their football operating costs directly from football income last season.
It puts both in the firing line if the AFL brings in equalisation measures in a bid to control the gap between rich and poor clubs.
"There may be moves to temper our capacity to grow and that will be an interesting debate in the next six to 12 months," Mr Rosich said.
But he said playing a grand final and the chance to open the AFL season provided another growth spurt for the Dockers.
"We officially passed 45,000 members yesterday for the first time," he said.
"We expect that, in the early part of the season, we will no longer have reserved seating available, probably soon after our first home game, which is against the Gold Coast Suns on March 29.
"After last year, very few fans have decided not to renew their memberships and the level of new people signing up has been very high."
The rapid growth is shown in figures from last season compared with 2003 when the club had its first explosive growth and played finals for the first time.
In 2003, the Dockers had 25,000 members, a turnover of just under $20 million and made a contribution of just $1.9 million to the WA Football Commission.
Last year, membership reached 44,035, turnover was $46.6 million (after GST) and the club handed $4.8 million to the WAFC.
The Dockers have budgeted to increase the WAFC contribution to $5.6 million this year.
"We recognise it is a privilege to open the season," Mr Rosich said. "It's the first time in 20 years we have had that opportunity.
"These are the games that clubs want to be involved in - us, the players, coaches and also the supporters.
"That said, our core business is winning games of football and that is what we are focused on."