The technology is being trialled, thanks to Swansea Council teaming up with environmental charity Keep Wales Tidy.
Sea bins are bucket-shaped devices that rise and fall with the tide, collecting floating litter and debris.
As water is drawn in by a pump, it passes through a catch bag which then traps the waste.
Clean water is pumped back out, while litter and debris are safely contained for proper disposal.
Powered 24 hours a day, the sea bin at Swansea Marina has a capacity of 30 litres to collect waste.
Cllr Cyril Anderson, Swansea Council’s Cabinet Member for Community Services, said: “It would be a lot better if people didn’t irresponsibly drop their rubbish in the first place, but the trial of this sea bin shows we’re continuing to be innovative in all we do to keep our city and waterways as clean as possible.
“We’re delighted to have partnered with Keep Wales Tidy on the introduction of this technology and will continue to explore its effectiveness as part of the ongoing trial.
“Research shows about 80% of marine litter originates from land-based sources, so it’s important we do all we can to protect our marine environment and encourage people to either use bins or take their waste home with them.”
The initiative is being funded by the UK Government through the UK Shared Prosperity Fund.
The council say the sea bin is being regularly monitored to investigate what it collects and to check for any unintended impacts or interactions with wildlife.
