The arrival of the 29-year-old lock will be a major boost to the Scarlets as they prepare for the new season which includes a difficult Heineken Cup draw.
The transfer of Louw from French side Clermont Auvergne looked to be in jeopardy under new regulations brought in on February 8. But the Scarlets successfully appealed to the Home Office as Louw was signed before the regulations came into force.
Scarlets Chief Executive Stuart Gallacher was pleased to have wrapped the drawn out deal up. He said: "We're delighted and looking forward to Hottie joining us in a few weeks."
The Scarlets will face Heineken Cup holders Toulouse, former champions Wasps and Scottish outfit Edinburgh following last week's draw for the pool stages of next season's competition
Carmarthen Quins are holding an exhibition to commemorate club players who fought in World War I. All welcome to the clubhouse on Friday afternoon to learn more about local history, or share any family anecdotes or artifacts.
Defence coach Shaun Edwards believes Saturday's clash against England - the 'form team in world rugby' - poses a huge challenge for his side but he is confident, with Wales beginning to show the defensive qualities displayed in the last two World Cups,
Women in the Ospreys region recently completed a Level 1 coaching course and are looking forward to putting their theory into practice in clubs and schools across the region. A women only course has been organised for the Scarlets region starting next week, full details at the end of the video.