The 27-year-old has won four caps for the Maori All Blacks and is a former New Zealand under-20s international.
Thomson is a utility forward who is able to cover second-row, blindside flanker and No 8 and will arrive in Llanelli at the start of next season.
“Blade’s Super Rugby experience will a welcome addition to the pack and the squad as a whole,” said Pivac.
“He is a very athletic, no-nonsense player with a big engine who will be an effective ball carrier both in the wide channels as well as in the middle of the park.
“Blade is highly regarded in New Zealand whilst an untimely injury impacted on his rugby in the last six months but he’s certainly a physical player who possess the skillset to play the Scarlets way.”
Thomson made his Super Rugby debut in 2013, where he played alongside Scarlets centre and Wales international Hadleigh Parkes, and has proved himself to be a dynamic, quick and skilful loose forward scoring seven tries.
The Champions Cup quarter finalists are losing Scotland captain John Barclay and Irish sensation Tadhg Beirne next meaning the signing of Thomson is a huge boost to the region.
“I’m really looking forward to heading north to join the Scarlets for the 2018-19 season,” said Thomson.
“They play an exciting brand of rugby, finished last season as champions and are continuing to push for silverware in both competitions. I’m excited to join such a world-renowned club but my focus is fully on finishing the current season on a high with the Hurricanes and hopefully lifting some silverware.”
