The WA man who drove his 4WD into the Swan River on Friday so his two friends could cast crab nets said the unusual fishing tactic was the result of some pub banter between mates earlier in the day.

On Tuesday, Dongara resident Jamie Koric's video of two friends sitting atop his Toyota Landcrusier as he drove it about 20 metres into the water had been viewed more than 131,000 times.

At its deepest point, water is wading over the top of the 4WD's bonnet as the shirtless men each throw a crabbing net into the river.The vehicle then turns and slowly makes its way back to shore.

The 24-year-old driver told WAtoday he and three mates had "floated" the idea over lunch at the pub and next thing he knew, they were down at the river.