Around 200 invited guests will attend the naming ceremony of the two inshore lifeboats, the Atlantic 85 Jacqueline Saville and the D class Stanley Whiteley Chadwick, which have both been funded by legacies from supporters of the charity.
The naming ceremony begins at 1pm and members of the public are encouraged to come along as well to join in with the celebrations (standing room only).
The Atlantic 85 is named in honour of Miss Pamela Jacqueline Saville, who lived in Cambridge until her death in August 2009.
Her father was a Merchant Navy Captain who was rescued by the RNLI after his boat was sunk. He was one of few survivors.
This rescue inspired Miss Saville to become a lifelong supporter of the RNLI. She was a life governor from 1992 and left a substantial legacy to fund the lifeboat at Mablethorpe.
The D class Stanley Whiteley Chadwick was funded by the legacy of Mrs Marian Chadwick in memory of her husband. Mr and Mrs Chadwick lived in Yorkshire and were great lovers of the coast.
Stanley was in the Royal Navy and had always admired the work of the lifeboat crews he had seen operating in the North Sea.
On her death in 2006, Mrs Chadwick left a generous bequest to the RNLI to fund a new lifeboat for the benefit of communities on the east coast.
During the ceremony, the lifeboats will be formally accepted into the care of the lifeboat station by Mablethorpe RNLI Lifeboat Operations Manager Dale Chapman.
He said: “Lifeboat naming ceremonies are always great occasions which give RNLI volunteers and supporters the chance to celebrate our charity and the generosity of people like Miss Saville and Mrs Chadwick.
“Without donations and legacies like theirs, the RNLI would be unable to carry on its vital lifesaving work.
“We are very much looking forward to being able to acknowledge their generosity and to welcoming many friends and fellow RNLI volunteers to our lifeboat station for what I am sure will be a very special day.”