The 35-year-old, ninth overall at the Amgen Women's Race in June, spent the 2017 season with Drops Cycling.
"I'm very excited to welcome Martina to Wiggle High5," said team manager Rochelle Gilmore. "It's a super exciting signing for our team. Wiggle High5 has been searching a strong, reliable and experienced rider to support our General Classification ambitions.
"Martina has a reputation for being very consistent and committed to her roles within a team, she's a rider we really needed to compliment our already strong line-up."
The veteran will look to put her all-rounder skillset to work across the spectrum of racing next season.
"I'm a good climber and time triallist and love stage races," Ritter said. "My favourite races are the Ardennes Classics and hilly stage races as the Giro d'Italia or Tour of California. I want to help our leaders to achieve big results because there is nothing better than winning as a team. One big goal will also be the World Championship in my home country."
Schweizer renews with Virtu Cycling
Doris Schweizer will ride on with Virtu Cycling next season. The 28-year-old has signed an extension with the squad, which raced as Team Veloconcept this year.
Switzerland's national champion in both the time trial and road race in 2016, Schweizer endured a challenging 2017. Derailed by injuries and illness, she registered DNFs throughout the season, but rider and team both remain committed to the future.
"I have to control myself, I got into overtraining because I didn't rest properly. I have really learnt, that when I train - I train, but when I don't I really have to rest well. I control it much more now, and my coach is really strict with me," said Schweizer.
"A lot of things went bad this year, but it was not because of the team or that I didn't try hard. With the girls and Carmen [Small, sports director], I have a really good feeling, and I think it is best not to change my environment again, because it would be too stressful, and I am already happy in the team," she says.
Small emphasised the importance of recovery.
"Doris had her season ruined because of illness and injuries, but she is a fighter and she knows what needed to be changed. Even though it can be really hard, she needs to take small steps and be patient, but then I'm sure we eventually will see her coming back to full strength," she said.
"When she is at her best she is phenomenal on the big climbs and also on the ITT's, but first of all we must help her find her way back to her old level and the peloton. She can be very important for the team, but it is a step by step progress to start with."
Orica-Scott Women celebrate 'most successful season yet'
Finishing the season with the top rider in the UCI World Ranking, Orica-Scott have enjoyed what sport director Gene Bates called their best ever season.
"The key to our most successful season yet has been a dedicated team of riders and staff committed to one another at every race we start," sports director Gene Bates said via a team release on Monday.
"Not every rider can achieve the final result at the finish line, but behind the scenes is an incredibly hard working and honest group of riders, who all deserve recognition for their efforts.
Katrin Garfoot got the Australian squad off to a strong start, sweeping the road and time trial races at the team's home national championships. Orica-Scott delivered further success early in the season with victories at the Santos Women's Tour – won by Amanda Spratt – and the Cadel Evans Great Ocean Road Race – won by Annemiek van Vleuten, before embarking on a successful campaign as racing picked up in Europe.
Van Vleuten went on to win stages at the Giro Rosa before claiming La Course by Le Tour de France as well as two stages and the overall at the Boels Rental Ladies Tour. Sarah Roy scored another WorldTour-level win for the team at the OVO Energy Women's Tour.
Van Vleuten's third place overall at the Giro Rosa and Gracie Elvin's runner-up ride at the Tour of Flanders were among the team's many other impressive results on the year, a year closed out on a high note with Van Vleueten's time trial world title in Bergen.
Bates committed to staying focused for the coming season.
"We are very proud of our achievements, but this year's success only spurs us on to greater things for next year," he said.