The St Helens club were relegated from the top flight in 2014, but took just two years to get back thanks to a second place finish in the Championship last term.
As they prepare for the new season there will be a triumvirate of new faces to call upon in the form of stand-off Julian Mogg, number eight Adam Thresher and scrum-half Martin Luckwell.
Mogg, who was part of the Bristol Rugby Academy programme and was capped by England at Under-18 level, makes the move west after two seasons with Newport.
“Joining Swansea RFC is a great opportunity for me to be involved with a new region,” said Mogg.
“There is a great team set-up and I know the players are looked after well. It is good to see such a positive vibe among the coaching team and around the club, and I am looking forward to playing at St Helens.”
Thresher joins after impressing for Swansea University, including a fine performance in their Varsity win over Cardiff earlier this year.
Luckwell, meanwhile, joins after spending the last four seasons with Merthyr, who were themselves promoted to the Premiership last season.
