Thousands of volunteers are visiting beaches in the UK to clean them up and record how much rubbish there is.
The Marine Conservation Society (MCS) has asked people to help clean up more than 400 beaches across the UK, as part of the charity's Beachwatch event.
According to the charity there has been a huge increase in the amount of litter left on UK beaches.
The MCS uses Beachwatch information to try and stop rubbish getting left on the beaches in the first place.
The charity says that litter that as well as being a mess, the litter is also a "major threat to many vulnerable marine animals".
In 2005 more than 3,500 people took part in the survey, collecting nearly 3,000 bags of litter.