There were three choices of routes, all starting at Worthing Leisure Centre and the longest stretching as far as Shoreham.
More than £116,000 has been raised so far, with the total announced shortly before midnight, when the women set off in a flock of pink t-shirts with glow accessories.
To mark the anniversary, there were plenty of special additions, including a spectacular glow performance by Smoking Hot Promotions at the start of the walk and at Worthing Pier.
First to complete the seven-mile route was Suneeta Kambam, 35, from Worthing, who was taking part for the first time.
Kelly Earle, 30, from Littlehampton was taking part for the sixth time and was first to complete the half-marathon route.
She said: “The atmosphere was amazing. Everyone was in high spirits. The event was fantastically organised. We got back at 3am and everyone was still cheering us on which we really needed during that last mile.
“St Barnabas House is a charity very close to my heart. I actually volunteer there and have done for one and a half years. It’s a good charity and helps a lot of people locally, so I want to do my bit.”
Crossing the 20-mile finish line first, having walked to the iconic Adur Ferry Bridge and back, were Ali Spear, 50, Ginny Cole, 51, and Lisa Oliver, 47.
Ali said: “We were walking to raise money for the Hospice at Home team, which I work for. It’s amazing and the volunteers are incredible.”
Sue Thom, 48, from Worthing took on the 13.1-mile challenge as part of White Meadows Wanderers, a team of 17 walkers.
Taking part for the third time, Sue said: “My friend Lucy Scriven is the superstar for our team. We are the largest team and every year we grow in numbers.
“I’m in a very fortunate position – I’ve never known anyone who has been in St Barnabas but it’s one of those situations where anyone could need them at any point so I’m happy to help.
“My friends have had in-laws and parents go through it and they couldn’t sing their praised highly enough. It’s a great cause, lovely people and we should all help them as much as we possibly can.”
The money raised will go towards funding the Hospice at Home service, which provides care for patients in their own homes across Worthing, Adur, Arun and Henfield.