Italy's foreign ministry said the group had been exploring underwater caves in the Vaavu Atoll at a depth of around 50 metres (165ft) on Thursday.
It gave no further details about the victims' identities or the cause of the accident, but said all five were Italian nationals and an investigation was under way.
The Italian Embassy in Sri Lanka was working to contact the victims' families and provide consular assistance, the ministry added.
In a statement posted on X, the University of Genoa expressed its "deepest condolences" and said the victims included a marine biology professor and her daughter.
According to Italian media reports, the divers were reported missing at around 1.45pm by the crew of a diving vessel they were travelling on, when the group failed to resurface.
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A large-scale search and rescue operation was launched by the Maldivian Coast Guard and the Maldives National Defense Force (MNDF).
"A body has been found among the five divers who dived in Vaavu Atoll," the MNDF said in a statement to Italian news agency ANSA.
"The body was found inside a cave. The other four divers are believed to be inside the same cave, which extends to a depth of approximately 60m."
The former England captain became the UK's first billionaire sportsman, with this year's list also featuring Liam and Noel Gallagher for the first time.
In the top spot, on £38bn, are Sanjay and Dheeraj Hinduja and family. They were also No. 1 last year under former family head Gopi Hinduja, who died in November.
They own the India-based Hinduja Group, a sprawling conglomerate that employs around 200,000 people globally.
This year's biggest gainer in the list is 41-year-old Nik Storonsky, the owner of fintech company Revolut.
His wealth is estimated to have rocketed from £6.97bn to £16.41bn - an average gain of nearly £26m a day - after a round of fundraising valued his business at £55.6bn.
Fellow Moscow-born billionaire Alex Gerko, the mathematician who set up trading platform XTX, also jumped from £8.74bn to £16bn, and sits eighth in the list.
There are also some notable fallers, such as Manchester United co-owner Sir Jim Ratcliffe, whose petrochemicals business Ineos had a tougher year and brought his fortune down nearly £2bn to £15.19bn.
Inventor Sir James Dyson is said to have taken an even bigger hit. He is now worth £12bn according to the list - £8bn less than last year.
New entries for 2026 include Liam and Noel Gallagher (£375m), whose coffers were supercharged by their sell-out Oasis reunion gigs, and Glastonbury organiser Emily Eavis.
The festival is now owned by a family trust, and experts have suggested it could be worth £400m.
David and Victoria Beckham are also believed to have doubled their wealth in the last year to make Sir David the list's first billionaire sportsman.
Boxing and snooker promoters Eddie and Barry Hearn are also said to crossed the billionaire threshold, while the King is estimated to be worth £680m.
There are now 157 UK billionaires, 20 less than four years ago, and the minimum entry level has dipped to £340m.
The compiler of the list, Robert Watts, called it a "tale of two exoduses" as one in six families who appeared two years ago don't feature in 2026.
"Many foreign billionaires who have been living in the UK have also dropped out because they have moved away," he said.
"We have also seen a sharp rise in the number of British nationals now resident in Dubai, Switzerland and Monaco. As UK nationals these people remain on our Rich List - wherever they now live."
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The flight of many ultra-wealthy people has been blamed on government action such as the ending of non-domiciled status, which allowed people to avoid tax on income earned outside the UK.
"These two exoduses pose challenges for the UK economy and its public finances," added Mr Watts.
"Will more of the wealthy now set up or grow their ventures overseas and in doing so create fewer jobs here? How much tax - if any - will Rachel Reeves' Treasury be able to extract from those affluent Brits who have now left the country."
The list is based on identifiable wealth, including land, property, and assets such as art and racehorses, or shares in publicly quoted companies. It excludes bank accounts, to which the paper has no access.
Sussex Police were called at around 7.50pm on Thursday to an address in Durrington Lane, in Worthing, after reports of concern for a woman's welfare.
Emergency services pronounced the woman dead at the scene.
The 37-year-old man, from Durrington, was arrested on suspicion of murder and assaulting a police officer.
Sussex Police said the victim and suspect were known to each other and believed it to be an "isolated" incident with "no threat to the wider community".
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Detective Inspector Amanda Zinyama, of Sussex Police, said: "This is a tragic incident, and our thoughts are with the woman's loved ones at this difficult time.
"We are in the early stages of a fast-moving investigation, and officers are carrying out extensive inquiries to establish the full circumstances."
Police are not currently looking for anyone else over the woman's death, but extra officers will be in the area while the investigation continues, the force said.
It comes as an investigation by energy regulator Ofgem found the supplier failed to meet standards required when installing prepayment meters, and that it breached licence conditions designed to protect vulnerable customers.
Up to £70m of energy debt will also be written off as part of the agreement.
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British Gas had previously agreed to provide a £22.4m voluntary support package specifically to support pre-payment meter customers.
The regulator described the investigation as one of the most detailed and complex in its history.
What happened?
Some vulnerable customers who were in energy bill arrears had their homes broken into so that agents acting for the utility company could install a pre-payment meter.
The practice of seeking involuntary installation of prepayment meters took place between February 2018 and February 2023, when it was stopped, having been uncovered by The Times newspaper.
The company, however, had been made aware of meters being installed when not appropriate through an external review in 2018 and an internal audit in 2021, Ofgem found.
"It was clear that some customers who had an involuntary prepayment meter installed were not treated with the care and respect that they deserved," British Gas said on Friday.
"There were also errors in identifying some customers in vulnerable situations who should have been excluded," it added.
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British Gas has apologised and has since strengthened governance, oversight and safeguards for vulnerable customers, it said.
Chris O'Shea, group chief executive of British Gas owner Centrica, said: "What happened should never have happened, and I am sorry to the prepayment customers who were affected.
Tim Jarvis, chief executive of watchdog Ofgem, said: "It is clear that British Gas fell short in its treatment of an unacceptable number of vulnerable customers who had a prepayment meter installed without consent, and it's right that they've taken action to put things right.
"Because of our action customers will receive a substantial package of redress, compensation and debt write off."
He added: "The installation of prepayment meters under warrant should only be a last resort, with rigorous checks to ensure debt is recovered lawfully, proportionately and safely."
Smart pay as you go meters were a "positive choice for many customers" instead, according to the boss.
Compensation for customers
Some 40,000 customers who had a prepayment meter installed without their permission between 2022 and 2023 are already receiving compensation from suppliers.
While compensation to affected customers has already been paid, more has been agreed for energy users impacted from 2018 to 2021.
British Gas said it would now undertake a comprehensive review of its customer records and provide redress and compensation wherever possible for affected customers.
Customers do not need to take any action and will be contacted directly by British Gas.
The state-owned body entered into a nearly four-year agreement for "strategic communications" and "public relations services" in March last year.
It was the same month Lee Castleton, famous for being portrayed in ITV's "Mr Bates" drama, became the first sub-postmaster to launch High Court action against the Post Office and Fujitsu, maker of the faulty Horizon software.
The Post Office contracted DRD Partnership, which says it "promotes and protects clients' reputations at moments of challenge and change", from March 2025 to January 2029 for £2.4m.
DRD representatives were present at a recent High Court hearing on Mr Castleton's case.
The value of this deal was double that of the Post Office's preceding strategic communications contract with reputation managers Lexington Communications, running for four years from July 2022.
Services listed on DRD's website include litigation communications and crisis and reputation management.
The firm also has lower-value public contracts with West Midlands Fire Service and Hampshire and Isle of Wight Fire and Rescue Service, worth £170,000 and £40,000 respectively for far shorter periods of just under seven and just under four months.
Other than these public tenders, the public relations company does not disclose its clients.
But the contract with DRD is just one entered into by the Post Office.
Another is worth £960,000 for PR services such as "executive profiling and reactive media opportunities" and "consumer media positioning and narrative development" with PR agency Boldspace for just under four years, according to the government's tender website.
No Horizon PR work is done by Boldspace.
In total, the combined value of these Post Office communications contracts is £3.36m.
Both Boldspace and DRD declined to comment.
The Post Office also has internal media relations and marketing staff.
A Post Office spokesperson said: "Contracts are openly and transparently published on the government's Find A Tender website."
Defending new cases
It comes as the state-owned entity defends cases related to the Horizon IT scandal in which hundreds of sub-postmasters were wrongfully convicted of fraud and wrongful accounting.
Many more racked up large debts, became ill, or suffered a relationship breakdown as they sought to plug the incorrectly generated financial shortfalls. Some died by suicide.
As well as defending Mr Castleton's claim – as a Post Office lawyer argued in a January High Court hearing, "it has a duty to its shareholders to defend" – another Horizon victim is having her High Court case challenged.
Janet Skinner filed her case in December as she sought full redress for her wrongful conviction, having not received a final payment, being offered an insufficient interim sum and being asked for six different expert reports, her solicitor said at the time.
The Post Office is also fighting cases where the Horizon predecessor, called Capture, was used in convictions.
Two such prosecutions have been referred by the Criminal Cases Review Commission (CCRC) to the Court of Appeal as a potential miscarriage of justice.
Why does it matter?
The money would have been better spent aiding sub-postmasters as the spending was unjustified, according to Simon Goldberg, a solicitor for Lee Castleton and Janet Skinner.
"As an organisation that is owned by the Department of Business and Trade, it is effectively funded by the taxpayer. This means that there is a duty of care to ensure that its expenditure is justified and necessary, neither of which is the case here," Mr Goldberg said.
"Other than when it comes to paying redress to victims of the scandal, [the Post Office] spends money like water."
The money would be better spent on redress or supporting the charities set up to aid sub-postmaster victims and their families, Mr Goldber added.
"That could and would undoubtedly help with reputational issues, but the Post Office seems incapable, on any level, of taking positive measures like this."
So far, the Post Office's PR efforts have been unsuccessful, he said.
"For all the money it spends on crisis PR, the public has not seen any improvement whatsoever in the reputation of the organisation, and speaking from the coalface, the sub-postmaster cohort resents the largesse with which public funds are spent, except on the only deserving cause which could help to right past wrongs – namely, the victims and their families."
A Post Office spokesperson said: "We are an essential service for communities across the UK, and external communications agencies help us to promote the banking, parcel and travel products that our postmasters offer, increasing their relevance and income.
"The Post Office only runs the Horizon Shortfall redress scheme, which has now closed, and as at the end of March, had paid out £917m.
"We have begun a long-term programme of restorative justice for those impacted by the Horizon IT scandal."
How much has been spent?
From January 2025 to late February this year, £313,386.66 was spent on the two companies, according to information obtained via Freedom of Information (FOI) legislation.
Boldspace received £134,517.66 during the period, mostly for content partnerships, social media, and product PR, the Post Office said.
DRD received £178,850.
The contracts, however, are on the lower end of those entered into by the Post Office.
Other recent tenders include a £14.4m three-year contract with one of the so-called big four accountancy firms, KPMG, for forensic data mining.
Another £14.4m four-year contract was entered into between the Post Office and Code Worldwide for customer database management, hosting and maintenance, and campaign management.
Jobs are being cut at the company's head office as part of restructuring and a transformation plan, which includes franchising more than 100 directly managed branches.