Travellers who pitched up at the West Lindsey Leisure Centre in Gainsborough at the start of the week could have another two days on the site before moving away.
Around eight caravans have been at the leisure centre on The Avenue since at least the afternoon of Monday, June 12, with West Lindsey District Council in the process of trying to remove them.
However, this could take until Friday.
West Lindsey District Council chief operating officer Mark Sturgess said: “We are aware that travellers have moved temporarily on to the Gainsborough Leisure Centre site.
“We are taking steps to ensure that they are moved off the site as soon as possible while complying with our legal obligations.
“At the present time we are anticipating that the travellers will move off the site on Friday, June 16.”
A post on the West Lindsey Leisure Centre Facebook page said: “We are aware that there are a number of travellers currently occupying the car park.
“We are working closely with the local authority to manage the situation.
“We aim to have this matter resolved as soon as possible and apologise for any inconvenience this may cause to our visitors.”