The midfielder, from Garstang, has joined the Shrimps on a season-long deal from Burnley for a third spell at the Mazuma Stadium.
The 23-year-old first joined them on loan in January 2020, along with Clarets team-mate Ryan Cooney.
Both returned last season, though Phillips was recalled on deadline day in January and then loaned out to Accrington Stanley.
Cooney made his move permanent after last season’s promotion, while Phillips returns after his two previous spells yielded a total of 14 goals in 44 appearances.
“I’m absolutely delighted to be back,” Phillips told the club website.
“Obviously I know the club really well, it’s going to be a great test this year in League One.
“I think the manager has put a great team together, it looks like he’s signed some strong players.
“There’ll be a lot of good games in the league, playing against the big teams which will be good for the fans. I’m looking forward to it.
“I knew from when I did leave that the team would push on and I knew they’d be there or thereabouts in the play-offs, and I was really happy for them that they got promoted in the end.
“It’s been a long time coming. As soon as I got the phone call from the gaffer, I was just so excited and I wanted to come back immediately.
“I turned down a lot of other clubs to come here. Morecambe has a place in my heart, and ever since I knew they were interested, I was excited to come back.”
Phillips’ time with Accrington means he knows what to expect in League One for the new season.
He also adds further goals to the midfield department as the Shrimps prepare for the opening day a week on Saturday.
“He is someone I’ve looked at for a wee while now. Obviously he was very successful here last year in League Two,” said Morecambe boss Stephen Robinson.
“He provides that quality, he’s got a range of passing and he scores goals, and we’re going to need goals to make sure we stay in this division.
“There’s real fighting competition for places, I don’t take anybody on loan that have to be guaranteed to play but sometimes when you have lots of quality in the building, then it raises everybody’s standards and Adam’s certainly one of those boys.
“You can’t have too many of those boys with us, there is a step up in standard and quality, especially at that top end of the pitch.
“To get a midfielder that scores goals, we’ve already got (Aaron) Wildig, Alfie’s (McCalmont) got a record of goals and now Adam’s got a record of goals as well, so it gives us plenty of choices - a headache for myself, but that’s what you need at this level.”
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