Police said they had been warned about the unauthorized encampment just before 7 p.m. on Monday. A total of 35 caravans and 40 vehicles were reported to be in the field behind Places Leisure at Passfield Avenue in Eastleigh.
Officers visited the site and said they would continue to monitor the situation.
The force also worked with the landowners and their groups in the area to “search for a suitable solution”.
On Wednesday morning, police had used Section 61 powers to ask them to leave the area.
A spokesman for the Hampshire Constabulary said: “Following an assessment of the circumstances and in consultation with the landowners late last night (July 12), the criteria for the use of Section 61 powers have been met.
“A request has been made for the encampment to vacate the area, which they have since complied with.”
Eastleigh Borough Council said they have closed the paddling pool at the leisure center with immediate effect.
The pool has since reopened after being emptied, cleaned, refilled and water quality tested.
In a statement, Eastleigh Borough Council told Metro.co.uk: “Council officials have already visited the encampment (Tuesday 12 July) to ask travelers to leave the site and we are continuing to monitor the situation.”
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Two recent unauthorized encampments at Chalcroft Way and Fleming Park cost the council around £5,000.
On 24 May, a total of 22 caravans set up camp in Fleming Park, land owned by the council.
Two days after arrival, the travelers left the park.
That same week, an unauthorized traveler’s camp prevented more than 1,000 people from playing football at the Stoneham Lane Football Complex.
Travelers set up camp for a total of 29 hours from Monday, May 23, before leaving the Eastleigh complex on Tuesday following police intervention.
The Hampshire FA site has suffered damage to the height barrier and the grass pitch and a total of 94 football teams were unable to play or train their matches during this period.