A search is underway in Portugal for a 23-year-old British student who disappeared after attending a boat party in Lisbon, leaving his family desperately trying to establish what happened to him.

Julian Amaral, who lives in High Wycombe with his parents, had been visiting Portugal with his family when he attended the Vida de Jovem Fest boat party on Tuesday, 1 September.

The event took place aboard a vessel travelling along the Tagus River, with around 200 people reportedly attending. Julian was at the party with his cousin, but at some point during the evening he disappeared and has not been seen since.

According to his older sister Cassandra, Julian told his cousin that he was going to the toilet shortly before the boat returned to Lisbon. She said:

"Around 11.20am he told my cousin that he was going to go to the toilet before they get back to Lisbon. So he went to the toilet... and he just never came back."

His cousin subsequently began asking other people at the party about Julian and waited for him as passengers left the boat. However, Julian did not appear. The vessel eventually returned to Lisbon around midnight and docked at Rocha Conde de Óbidos. Two security guards reportedly saw Julian leave the boat, but were unable to establish where he went after disembarking.

At the time of his disappearance, Julian was reportedly wearing a white T-shirt and dark grey long shorts. His family has shared images of him as part of their appeal for information, including a photograph in which he is highlighted to help members of the public identify him. The description of his clothing could be particularly important for anyone who may have seen him after he left the boat or in the surrounding area.

His disappearance was reported to Portuguese police, with a family member attending a police station to make a formal report.

The case has since developed into a wider search operation, with authorities examining the circumstances surrounding Julian's disappearance and attempting to establish his movements after he left the boat.

On Friday, 4 September, searches were underway in the Tagus River around the Rocha Conde de Óbidos area. The operation involves personnel from the Lisbon Port Captaincy and the local Maritime Police, while divers have also carried out searches in the water.

An Air Force helicopter was brought into the operation from around midday, adding an aerial search to efforts already being conducted from the river and shoreline.

Portuguese authorities have also been contacting hospitals as part of their efforts to determine whether Julian may have been taken for medical treatment after leaving the boat.

The circumstances surrounding his disappearance remain unclear.

Julian's family is particularly concerned because he does not know Lisbon well and does not speak Portuguese. His mobile phone has also been switched off, making it considerably more difficult for relatives and investigators to establish where he may have gone.

His sister has said that the family does not believe he would simply leave without contacting someone. She said:

"They said that he must have left already. Then he started to panic because he had barely any battery left and my brother's phone was not coming up at all. We basically just have not seen or heard anything since."

The family has also raised questions about whether Julian could have entered the water, although they do not believe this is the most likely explanation.

Cassandra described her brother as a strong swimmer and said that, despite having consumed some alcohol, his cousin did not believe he was drunk.

"He is an incredible swimmer. I know that if he dropped in there, he would have swam...and honestly, I don't think that's the case."

The family is now appealing for anyone who attended the boat party, was in the area around the time Julian disappeared, or may have encountered him afterwards to come forward.

Cassandra has also expressed fears that Julian may have been taken against his will, although there is currently no confirmed evidence publicly establishing that he was kidnapped or that he has been the victim of a crime.

"He wouldn't take a drink from somebody. He's very, very glued on. I know everybody always says it's out of character, but genuinely it's out of character for him."

Cassandra added:

"I know Julian's character. He's one of those people, he just always sorts himself out. He's very, very self-sufficient. If he needed help, he would approach anyone and just beg to use their WhatsApp."

The family has been particularly concerned by the fact that Julian's phone is no longer active. Cassandra said:

"To be honest, I don't think he's with his phone. I've been hearing from a lot of my relatives that live in Portugal that there are so many cases of young travellers going to Lisbon and getting drugged, kidnapped, some believed to be trafficked."

Her comments reflect the family's fears, rather than a confirmed explanation for Julian's disappearance. Police have not publicly established that he was drugged, kidnapped or trafficked, and investigations into what happened remain ongoing.

Julian had travelled to Portugal to spend time with relatives and was reportedly staying at his cousin's home during the trip. His family has connections to the country and has visited regularly since he was a child. The family had travelled to Lisbon for two weddings, one of which may no longer take place as planned following Julian's disappearance. His relatives are now concentrating on finding him and have been working with Portuguese authorities and the British Embassy.

The organisers of the Vida de Jovem Fest have also acknowledged the disappearance and said they are cooperating with the authorities.

In a statement shared online, the organisers said they wanted to "manifest our concern regarding the disappearance of Julian".

They added:

"In this moment of apprehension, we appeal to everyone who may have any relevant information about his whereabouts to communicate it to the competent authorities, contributing to his rapid and safe reunion."

The organisers also said they were prepared to "collaborate with the competent authorities, providing all the support and information that is within our reach and that can help clarify the situation".

The disappearance has prompted a wave of concern online, with members of the public expressing hope that Julian will be found safe. One person wrote:

"These stories are so scary! I hope he is found safe and alive!"

Another asked:

"Why do things like this keep happening!?"

A third person said:

"Really praying he gets home safe!!"

The case comes during a period when Lisbon is experiencing high numbers of international visitors, with the Portuguese capital being a major destination for young tourists and students. Boat parties and nightlife events along the Tagus are also popular with visitors, meaning large numbers of people can be moving between vessels, waterfront areas and the city during late-night events.

However, authorities have not suggested that the boat party itself was responsible for Julian's disappearance, and the investigation is still focused on establishing what happened after he left the vessel.

The fact that witnesses saw Julian disembark has become an important part of the investigation, as it suggests investigators may be able to reconstruct his movements after the boat returned to Lisbon.

At present, there is no confirmed explanation for why he disappeared.

Portuguese police have been carrying out enquiries while maritime authorities have expanded the search to the river. The involvement of specialist divers and an Air Force helicopter indicates that investigators are considering the possibility that Julian could have entered the water, although searches are also taking place around the surrounding area.

His family is continuing to ask members of the public to provide even the smallest piece of information that could help establish where he went.

Cassandra said:

"Even if it's the smallest piece of information, even if you saw him for a split second, we will appreciate it and we really want to hear what you have to say."

"Anything that could help us to find out where he is will be a massive help. We're all just praying for a safe return. We do genuinely think that we will find him or at least find out what's happened. We do think that."

The family has also issued a direct message to Julian as the search continues.

Cassandra said:

"Stay strong and the family will never ever stop looking for you."

For now, the investigation remains ongoing in Lisbon, with Portuguese authorities continuing to search for the missing 23-year-old and his relatives waiting for answers.

Anyone who may have seen Julian after he left the boat, or who has information that could help establish his whereabouts, is being urged to contact the Portuguese authorities.