Backs Hallam Amos and Jack Dixon crossed for first half tries with fly half Sam Davies kicking eight points for a comfortable half time lead.
It was a deserved reward for Danny Wilson's side as despite a fast start from Samoa, Wales more than matched the physicality of the Islanders - a penalty from Fomai Ah Ki their only score.
Wales' hard work in the first half was then rewarded in the second as they added four further scores. Carwyn Jones, Sion Bennett, Ieuan Jones and Elliot Dee all crossed as Wales took full advantage of a tiring Samoan outfit to start their tournament with a bang.
The first half had begun with the Samoans on top, their powerful forwards initially causing Wales some problems. There remained a feeling though that when Wales spread the ball wide, they would cause trouble. Amos did just that for the opening score as he dived over in the corner though Davies put the conversion wide.
Samoa did reply with a penalty from wing Ah Ki but that was as good as it got for them in the first half. Dixon soon added a second for Wales, squeezing over through a pile of bodies and with Davies finding his range from the tee, he kicked Wilson's men into a comfortable half time lead.
The fly half converted Dixon's score and added two long range penalties for an 18-3 advantage. It could have been even better though, skipper Ellis Jenkins tackled into touch just short of the line while No. 8 Ieuan Jones was held up when a score looked certain.
After gaining a platform upfront, Wales then showed their clinical side as they ran riot after the break. It had been a slow start initially but when Samoa lost No. 8 Elekana Laupola to a nasty looking neck injury, they struggled to manage a response.
Carwyn Jones and replacement Bennett then added quick fire scores and with Davies converting both tries, Wales were now out of sight. A third second half try soon arrived, No. 8 Ieuan Jones galloping over before both sides flooded the game with a series of replacements.
The breaks in play did hinder the flow of the game and Samoa refused to give up but Wales were worthy winners, replacement Dee scoring right on the final whistle.
Tries: Hallam Amos, Jack Dixon, Carwyn Jones, Sion Bennett, Ieuan Jones, Elliot Dee; Conversions: Sam Davies (3); Penalties: Davies (2).
Penalites: Fomai Ah Ki.