For three of its ageless swimmers, one could be mistaken that it's the fountain of youth.

But that only draws fits of laughter from Rod Oliver, 68, Ray Brien, 66, and John Pugh, who, at 77, can blame his fine wrinkles on spending too much time paddling through water.

Pugh has incredibly swum more than 10 million metres in Tasmanian waters - since he started counting in 1991 - far exceeding the purpose of the Masters Swimming Australia million-metres program.

"I have just broken another (milestone) this year, so I've actually finished it. That's why I look so old," Pugh grins.

But together, between Oliver, Brien and Pugh, they have swum more than halfway around the world.

It equates to 22,000 kilometres, which is a combined 440,000 standard laps of an Olympic pool.

Or, in other words, from Launceston to Pugh's birthplace, Bulawayo, the second-largest city in his native Zimbabwe - and then back again in the longest tumble turn imaginable.

Pugh is the only Launceston Masters Swimming Club member to reach 10,000km, the magic mark taking 23 years and nine months to achieve.

"To use a landmark to illustrate a distance, Sydney to Auckland is about a million metres (1000km)," Pugh said.

"I've done that 10 times and it's getting a bit boring now."

Oliver first got into a warm Ipswich pool in 2000 and is not far behind, passing 7000km in the heated depths of the Launceston Aquatic Centre this year.

Brien recently reached the 5000km mark after he started noting down distances two decades ago, as the threesome push their way around the globe.

"If we totalled all the million-metre members in the (Launceston) club, we would have close to 45 million metres, as a lot of people are one and two million metres," Brien said.

Other than total madness, the million metres program is to recognise swimmers of all ages at the one, two, three, five, seven and 10 million-metre milestones.

"The idea is, if you watch these people here," said Pugh, pointing to the bodies swimming laps of the pool, "they are swimming endlessly up and down, day after day."

"So the idea of this program is to give an incentive to try and swim further and faster."

The keen million-metre members always prepare for a long dip.

They dive into the aquatic centre pool, swimming until they hit the wall.

Up and down, all the while looking down that black line, lap after lap.

Amid the monotony, the motivation is there.

"What happens is, when I first tried one million metres, you just keep plugging along," Oliver said.

"Then suddenly, as you come towards the end, the incentive is to up your work rate to achieve that target.

"It's an interesting exercise in terms of how to attack a large project and you break it down into smaller sections . . . say 50km lots, and do that 50 and do the next 50."

Did he say 50km in a pool?

Well, not in a day, at least. Phew.

Most Launceston million-metres members swim 2000-2500m in a day, three times a week.

That's getting there.

"The hardest part for me is keeping a log of what you're doing when you're swimming," Brien said.

No one else is there to record these breathtaking measurements, other than the swimmer keeping count while crashing into the wall amid the wash.

"It's an honour system and no one challenges the distances you put out," Pugh said.

"What's the incentive to cheat?

"Other than to do 10 million metres before you die."

The long swims these days have become a tad more comforting since the indoor aquatic centre opened in Launceston in 2009.

Before then, there was the odd lake, even the sea, but mostly the outside pool at Windmill Hill.

Oliver remembers the bitterly cold days in winter, the breeze kicking off his shoulders during strokes and the mad scurry back to the change rooms dripping wet.

"These days, we get it a bit easier in the new pool," Oliver said.

"We all have vivid memories of swimming in the old outdoor pool, particular in the middle of July with the howling northwesterly."