The Portsmouth Coastal Waterside Marathon is back on Sunday.
This year it will be run alongside a new race, the Harbour 50k Challenge, as well as the Festive Half Marathon.
All three multi-terrain races have sold out and it means organiser Rob Piggott will welcome around 2,000 runners in total.
The events start at the Pyramids Centre with runners heading out along Southsea seafront towards Eastney, then up the Eastern Road.
For the 50k race, runners will take in the Portsmouth Coastal Waterside marathon route and add in a loop around the west side of Hayling Island.
Then they return to the finish line at the Pyramids.
The half marathon follows the same route as the out-and-back marathon course with the turn point at halfway.
Anthony Clark and Gemma Bragg won the marathon in 2014.
Clark, of Poole Runners, delivered a quality performance to win in muddy conditions with an impressive time of 2hr 41min 33sec.
Bournemouth AC athlete Bragg was first lady as she completed the tough course in 3.09.42.
Tomorrow the new Portsmouth ultra race will be the first event to get started with runners heading off at 8.30am.
Next to go will be the marathon runners at 9.15am, with the half marathon at starting at 10am.
Believe and Achieve Events Ltd Portsmouth host the races to raise money for the local RNLI lifeboat station based at Eastney.