The arrival of Nathan Burns and Michael McGlinchey this season made starting spots scarce at the Phoenix and Boyd has taken the chance to move to Europe.
"It's been my dream since I was a kid and we came across this club and it suited me and suited my playing style so that's how it came about," Boyd said today. (fri)
"It's really encouraging to have four years there. I just want to keep improving and learn a lot over there and that's the main reason I went there.
It's understood the Phoenix and Boyd had discussed a contract extension beyond this season but the money on offer wasn't up to Boyd's demands.
Boyd recently scored four goals, three of which were penalties, in 17 minutes for the Phoenix's reserve side against Southern United in the national league.
The 20-year-old, who made his All Whites debut last year, quizzed France-based Kiwi Bill Tuiloma about the challenges of living in Europe before signing with Vitoria.
Boyd will join a growing contingent of young Kiwis in Europe, alongside Ryan Thomas plays for who PEC Zwolle in Holland, while Marco Rojas has been loaned to Swiss club FC Thun.
Boyd said he hadn't spoken to All Whites coach Anthony Hudson about his shift but expected to chat with him shortly.
Hudson, who has pushed for a youth movement in the national side since taking over last year, told the New Zealand Football website that Boyd's impending change of scene was a positive one for his career.
"Tyler is an exciting young player, a good character with a big future in the game and the move will be good for him at this point in career," Hudson said.
"He's been scoring goals in the ASB Premiership for the Phoenix [reserves] and a move to Portugal will ensure he keeps progressing and developing his immense talent which will obviously benefit the All Whites."
Despite not being able to crack Merrick's rotation on a regular basis, the Phoenix coach wished Boyd well on his departure.
"Tyler is a good player who's just turned 20 and obviously not happy about the amount of starting game-time he's getting and I think he's a good quality player that will take this opportunity and make the most of it," Merrick said.
The Phoenix will play the Victory in Melbourne on Sunday.