Cristopher Andres Picado Ramirez, 28, is also said to have assaulted a woman from Argentina as well as two minors from Costa Rica.
It comes as Bear Grylls, Holly Willoughby, and other celebs are in the South American country filming a new Netflix survivor show, expected to give the country a tourism boost.
Picado Ramirez allegedly attacked some of his victims inside the bathroom of a bar in Santa Teresa while others were assaulted at parties held on farms near the resort’s famous beach.
Picado Ramirez, who describes himself as a surfing teacher online, is accused of attacking at least seven women in total aged 18 to 24 between 2019 and 2022.
An eighth case of an attack on a foreigner is still pending DNA results, according to local media.
Feminist and human rights groups held protests in front of local court buildings as he stood trial.
Judges were heavily criticised for releasing him on bail after he arrested.
None of the British women, who were among the first to report attacks, appeared at a two day court hearing in late April, but are understood to have given evidence from the Costa Rican consulate in London.
The trial was supposed to conclude last week, but stalled after Picado Ramírez, who is said to have Asperger’s, presented one of his alleged victims as a witness in his favour.
The woman, who was described as being his girlfriend when he was 24 and she aged just 13, is being put forward as a character witness.
Walter Brenes, lawyer for three of the victims, said he was “completely baffled,” adding: “In a hypothetical defence of myself, I would not offer a victim as evidence, knowing that the victim is still a victim.”
The trial is now set to conclude this week.
Members of the cast and crew of the new Netflix survivor series, Bear Hunt, hosted by Holly and Bear Grylls, are likely to have visited Puntarenas, a renowned cultural hub, from across the Gulf of Nicoya where many have been pictured staying in Guanacaste Province.
Cast members also include Lottie Moss, Mel B and Boris Becker.
According to local media groups, the Santa Teresa Feminist Movement organisation reported at least 25 cases of sexual assault against tourists between 2022 and 2023, but accused the port town’s officials of doing too little to tackle the problem.
The town has just nine police officers for a population of some 135,000.
There are almost no police patrols at night and tourists are invited to large-scale unlicensed parties and local mansions and farms.
Officials have been accused of having a poor attitude towards women who attend.
Campaigners say sex attackers make friends with tourists and find out when they are set to leave, attacking them close to their departure date so that they are less likely to stay and support a prosecution.