An initial inquest was told the three were declared dead at the scene of the crash.
The hearing was adjourned pending the outcome of further histology and toxicology tests.
Sophie Russon, 20, and Shane Loughlin, 32, were both injured but survived.
Image: Shane Loughlin and Sophie Russon survived the crash
Image: Tributes were laid and a vigil was held at the crash site
The accident happened near the St Mellons area of Cardiffon the A48(M).
A Volkswagon Tiguan veered off a slip road approaching a roundabout at 2.03am and came to rest in some trees.
The five were not discovered until Monday 6 March, around 46 hours after the crash took place.
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March: Vigil held for Cardiff car crash victims
The Independent Office for Police Conduct (IOPC) is continuing to investigate the length of time taken by Gwent Police and South WalesPolice to find the group.
Court papers seen by Sky News reveal the group had been drinking alcohol and inhaling nitrous oxide, commonly known as laughing gas, prior to the collision.
Image: The scene near the St Mellons area of Cardiff
The group had been on a night out at The Muffler social club in Newport on the evening of 3 March, before travelling just under 40 miles (64km) to the Trecco Bay Caravan Park in Porthcawl.
They were last seen at about 2am in the Pentwyn area of Cardiff, where a sixth member of the group was dropped off.
The details emerged at the hearing of Joel Lia at Cardiff Magistrates’ Court, which was held behind closed doors.
Lia, 28, was the sixth member of the group who had been driving the vehicle an hour before the crash.
He was charged with driving without a licence or insurance in Porthcawl.
According to the court document: “All other persons in the vehicle were intoxicated, by Joel’s admission, as they had been drinking alcohol and inhaling nitrous oxide throughout the course of the evening.”
Lia’s case is being handled under a system called the single justice procedure where magistrates deal with non-custodial criminal prosecutions in private.
He pleaded guilty to both charges and the case was adjourned until 24 August.
A body has been found in the search for 23-year-old runner Jenny Hall.
She was last seen leaving her home in Barracks Farm, County Durham, in her car just after 3pm on Tuesday.
Police said there are not thought to be any suspicious circumstances after a body was found in a very remote area in Teesdale on Sunday morning, five days after she went missing.
Image: Jenny Hall went missing on Tuesday. Pic: Durham Constabulary
“We’re sorry to report that officers searching for missing woman Jenny Hall, have sadly found a body,” Durham Constabulary said in a statement.
“Officers carried out an extensive search alongside specialist partners and have been working around-the-clock to locate Jenny after she went missing on February 18.
“The body was found in a very remote area in Teesdale just after 9.30am today.
“Formal identification has yet to take place. Jenny’s family have been notified and are currently being supported by specialist officers. They have asked for privacy at this devasting time.
“It is not believed there are any suspicious circumstances and a file will be prepared for the coroner.”
Her car, a red Ford Focus, was found on Wednesday parked on the B6278, near remote moorland between Eggleston and Stanhope.
Mountain rescue teams, specialist drones and sniffer dogs had been combing the Hamsterley Forest and the surrounding areas, where there are a number of running trails, this week.
Digital intelligence officers also carried out extensive inquiries into Ms Hall’s mobile phone, smart watch and running apps.
A fresh amber weather warning for heavy rain has been issued by the Met Office – with much of the UK already on alert for high winds and showers.
Northern Ireland, Scotland and the UK’s west coast and the Midlands have yellow warnings for wind on Sunday – meaning the possibility of transport delays and short-term power cuts.
There are also rain warnings in place for several parts of western UK.
The new amber warning has been issued for rain in south and central Wales and is in force from 3pm on Sunday to 6am on Monday.
An amber warning means danger to life from floodwater, homes and businesses are likely to be flooded, and there is a chance some communities will be cut off.
Winds across the west of the UK will increase throughout the morning with gusts up to 70mph in exposed areas, the Met Office said.
Zoe Hutin, a meteorologist at the forecaster, said Sunday is expected to be the “worst day” before conditions improve.
“The wind warning itself for the mainland UK ends at 6pm, but we can expect to continue to see quite blustery conditions even into the evening as the mainland rain itself pushes through.”
She added: “By the time people get up on Monday, we’ll still have some of the residual rain from that front in the far south-east of the country, and quite cloudy across England as well.
“But actually elsewhere, it could be a decent start.”
The Met Office’s yellow weather warnings for much of England and Scotland came into force at 6am and are expected to run until 6pm on Sunday.
A separate yellow warning for Northern Ireland came into force at 3am and runs until 3pm.
Image: Rain and high winds are expected across the west of the UK
Sir Keir Starmer has said the United States “is right” about the UK and Europe needing to take more responsibility for defence and security.
The prime minister, speaking at the Scottish Labour conference in Glasgow on Sunday, said he is clear Britain “will take a leading responsibility” in protecting the continent.
“Instability in Europe always washes up on our shores,” he said.
“And this is a generational moment. I’ve been saying for some time that we Europeans – including the United Kingdom – have to do more for our defence and security. The US is right about that.”
He added “we can’t cling to the comforts of the past” as it is “time to take responsibility for our security”.
Donald Trump sparked an emergency meeting of European leaders this week after he said European NATO members should spend more on defence, while the US should spend less.
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Will Trump and Starmer have a ‘Love Actually’ moment?
Sir Keir has said he will set out a path for the UK to spend 2.5% of GDP on defence, up from the current 2.3%, but has not indicated when that will be.
It is believed he may announce the details when he visits Mr Trump in Washington DC on Thursday, bringing forward the announcement that was expected in the spring when a defence spending review is published.
The prime minister reiterated the UK will “play our role” if required in Ukraine following a peace agreement after he earlier this week said the UK would send troops to be part of a peacekeeping force.
Image: Sir Keir will meet Donald Trump in the White House on Thursday. Pic: AP
However, his comments caused a row with Germany and Italy who said it was premature to commit to boots on the ground, although France agreed with the UK.
Sir Keir said: “As we enter a new phase in this conflict, we must now deepen our solidarity even further.”
He added: “There can be no discussion about Ukraine without Ukraine.
“And the people of Ukraine must have long-term security.”
No Europeans were invited either, sparking concern the US is pandering to Vladimir Putin.
Sir Keir has promised Mr Zelenskyy he will make the case for safeguarding Ukraine’s sovereignty when he meets with Mr Trump, who has called the Ukrainian president a dictator.
Mr Trump also said Sir Keir and French President Emmanuel Macron, who will visit the White House too this week, “haven’t done anything” to end the war.