The current provider, Silcox Coaches, is facing an uncertain future after experiencing financial difficulties.
The Pembroke Dock-based company has 28 school contracts with Pembrokeshire council, but BBC Wales understands it intends to file for administration unless a buyer can be found.
Edwards Coaches will be the new provider after half term.
Based in Pontypridd, Edwards Coaches is the largest family owned coach-company in the country employing over 500 staff and operating 260 vehicles.
Its managing director Mike Edwards confirmed all former Silcox home-to-school transport routes will be operated by Edwards when school term resumes on Monday, 6 June.
Silcox Coaches operates a further 18 public transport routes in Pembrokeshire and separate arrangements are being considered for these services.
An alternative coach company has been brought in to provide school transport in Pembrokeshire.