Julian Coles and Debbie Claridge set off from the RNLI's headquarters at Poole in Dorset on 1 January, aiming to visit all 238 of the charity's lifeboat stations.
The couple have been delivering three Betty's Pots, recycled jam jars which supporters use to collect 5p pieces to each station.
They also aimed to raise £10,000 from their mammoth trek in memory of two special RNLI supporters.
Ten months later, the pair from Didcot in Oxfordshire completed their trek at Hunstanton in Norfolk on 15 October, where volunteers were waiting to welcome them to the busy boathouse.
'It was a privilege to welcome Julian and Debbie,' said visits officer Kate Craven. 'We're so grateful to the pair of them to commit to funding the lifesaving work of the RNLI, while also working five days a week.
'The RNLI relies on the generosity of people like Julian and Debbie. And they even brought a cake.
'If there's one thing our crew are always grateful for, it's cake.'
Crew treat aside, Julian and Debbie's challenge was no piece of cake.
They estimate they have driven more than 10,000 miles in their Nissan Juke, along with taking 30 flights and 10 ferries to reach some of the RNLI's far-flung outposts.
'It took six months of planning,' said lorry driver Julian, 62. 'There's no relief on finishing it to be honest.
'There's sadness it's over, it's been our life for the last 10 months and it's left us slightly bereft and wondering what to do next.'
He added the Hunstanton crew showed them around the station and its craft - before the call came in to launch cake .
Both Julian and Debbie are members of the Marlborough Social Club in their home town, whose members raised £10,000 to buy a D-class lifeboat for the relief fleet in 1988.
Julian's late father Trevor, a keen sea angler who passed away aged 81 last year, was one of the leading lights in the campaign, which included a 24-hour darts marathon before members hit the target to launch D-407 Marlborough Club, Didcot.
Friend Alan Perks, who also passed away aged 65 last year, was another faithful RNLI supporter who helped inspire them to try to match the £10,000 raised by the Marlborough Club in 1988.
So far, their
JustGiving page has raised £3,000, while they have donated £1,500 in Betty's Pots and and hope to raise a further £2,000 with a bingo night, auction and raffle at the Marlborough Club on Friday, 18 October.
Julian and Debbie have also collected station pin badges from each stop-off on their route, which will be auctioned off as a complete collection.
Editor's notes
This year marks the 200th anniversary of both the RNLI and the founding of a lifeboat service at Hunstanton.
Hunstanton is one of Norfolk's busiest lifeboat stations, whose vonulteers operate both the inshore lifeboat Spirit of West Norfolk and search and rescue hovercraft Hunstanton Flyer.
They cover The Wash, a tidal estuary stretching for more than 100 square miles fed by five main rivers, along with parts of the north Norfolk coastline.
Like more than 200 RNLI stations around the coast of the UK and Ireland, the crew's lifesaving work could not be possible without the kindness of those who give donations or leave legacies to the charity that saves lives at sea.
Betty's Pots are named after Betty Frith, who was the Honorary Treasurer for over 20 years at the Hertford branch of the RNLI.
Supporters fill recycled small jam jars that you get containing breakfast jam or marmalade when you stay at a hotel or visit a café with 5p pieces, which are donated to the RNLI when full.
RNLI media contacts
For more information call Chris Bishop, Hunstanton RNLI volunteer Deputy Lifeboat Press Officer on 07584 147219, Clare Hopps, RNLI Regional Communications Manager, North and East on 07824 518641, or the RNLI Press Office on 01202 336789.