The English qualified player was signed on loan by Warriors head coach Jonathan Thomas earlier this year after impressing in a training match against Bristol Bears. He then made his Premiership debut off the bench in the games against Harlequins and Sale Sharks.
“Harri was brought to our attention a couple of months ago. We gave him the opportunity to come in on trial with a view to playing in the Premiership Rugby Cup,” said Thomas.
“Unfortunately for Harri and a lot of our young players the competition was cancelled which meant there have not been huge opportunities for him to shine. But he did play in the training match at Bristol where he showed some really high-class moments.
“He’s got great footwork and top-end gas which are the basic tools you need to succeed as a wing in the Premiership. Having taken his opportunity with both hands we have used him off the bench in the last couple of game and he has made an impact when he has come on.
“He’s at the start of his journey, so there is a long way to go, but he’s pretty level-headed. He’s impressed us with his attitude, his professionalism and his work rate.
“We are delighted to give him the opportunity and he deserves it for all the work he has done. We are trying to make sure that we have a balanced recruitment process.
As well as Williams, who will be joining from the Japanese Top League, Warriors have also recruited former Wales and Ospreys hooker Scott Baldwin from Harlequins and Scotland wing Duhan van der Merwe.
The 20-year-old Doel began playing in the Under 7s age group at Llandovery and played at every level through to the first team. He joined the Scarlets Academy five years ago and was a regular in the Scarlets A team in last season’s Celtic Cup.
He represented Wales at every age group from Under 16s upwards and played in the Under 20 Six Nations campaign last season. He will join a Warriors back division that already includes Wales centre Ashley Beck and follows another Wales U20 cap, Corey Baldwin, who went to Exeter Chiefs, out of the Scarlets and into the English Premiership.
He will be hoping to follow in the illustrious footsteps of Josh Adams, who joined the Warriors after he was released by the Scarlets and then managed to work his way into the Welsh team.
“I know Josh’s story very well and it was mentioned to me a couple of times when I was discussing coming here,” said Doel.
“Josh was released by the Scarlets when he was in the Academy, but he joined Worcester and did really well. He is now a regular starter for Wales and a potential British & Irish Lions star.
“I can remember hearing him saying that he couldn’t thank Worcester enough for giving him the opportunity and he’s a fantastic role model.”
Doel, who attended Coleg Sir Gar near Llanelli, is now in his final year of a mathematics degree at Swansea University.