Dalla Lana, 57, had contested the opening two rounds of the WEC alongside Aston factory driver Nicki Thiim and Zimbabwean Axcil Jeffries but steps away citing a desire to focus on business interests.
The Canadian won the GTE Am drivers' world championship crown in 2017 and claimed 17 class wins from 69 starts.
He came close to a class victory at Le Mans in 2015 before a late accident and mustered a best finish of third at the race in 2022 alongside Thiim and David Pittard.
“To race for Aston Martin, compete at Le Mans and win a world championship title, has been one of the greatest adventures of my life and has given me so many memories that I will cherish for the rest of my days,” said the Canadian.
“But the racing always had to stop at some point, and for me, that time has been coming for a while now.
“It has become increasingly challenging to find enough time to prepare and compete at the highest level; and to fight for a world championship you must be able to give your all.
“I’ve been lucky enough to race alongside some great drivers and great friends and compete against the very best in sportscar racing.
“I’ve been there as WEC has grown in stature and I’ve been able to drive the mighty V12, V8 and now the turbo-charged V8 Vantages at places like Daytona, Sebring and Le Mans. It’s been one hell of ride and I’m very grateful to have been able to take it all on board an Aston Martin.
“Thanks to all the incredible fans that have come out to watch us over the years, and I’d like to wish Aston Martin luck in the future. I’m sure going to miss it!”
IMSA SportsCar championship outfit Heart of Racing will field a GTE-spec Vantage for the first time at Spa for Ian James, Alex Riberas and Daniel Mancinelli after taking over the GTE Am class entry previously held by Dalla Lana, who has called time on a WEC career that stretches back to 2013.
HoR will continue to compete under the NorthWest AMR banner and use the #98 for the remainder of the season.
It won the IMSA GTD class title last year with Roman de Angelis, and took class victory in this year's Daytona 24 Hours ahead of the leading GTD Pro crews with its Aston Martin Vantage GT3.
James said: “The Heart of Racing team has had ambitions to compete in the 24 Hours of Le Mans, and the FIA WEC for some time.
“We are an ambitious group and to add WEC to what we have been fortunate to achieve in our other programmes over the past three years is an honour.
“Going for the Rolex 24 Hours at Daytona/24 Hours of Le Mans double is very exciting.
“I’d like to take the opportunity to wish Paul well in the future, and to thank him for giving us the chance to take over his entry for the rest of 2023.
“It will be a baptism of fire in Spa, but we hope to continue the successful heritage of the #98 plate in WEC.”
