
On Friday he will be presented to the media by his new club.
But Friday afternoon the hard work for the Dutchman will begin - when his comes face-to-face with a talented, but ageing squad in turmoil.
On Wednesday Valencia were thrashed 5-1 at home by Real Madrid, a result that pulls them down to fifth in La Liga and at the same time destroys what little morale they had left.
Valencia are at the bottom of Champions League Group B, with just three points from three games.
Koeman will certainly have his work cut out lifting Valencia back to the heights they hit in 2004.
Three year ago, Valencia enjoyed the most successful year in their history, winning the Spanish league, the UEFA Cup and the Spanish Supercup.
The future seemed bright for "Los Ches," despite the abrupt departure of coach Rafa Benitez for Liverpool.
Since 2004, though, Valencia have flattered to deceive. New president Juan Soler has spent heavily on rejuvenating the squad, but with the exception of striker David Villa his new signings have mostly been flops.
Soler has have four coaches and four sporting directors since 2004 - but no new trophies.
The present squad is an unhappy mixture of ageing Spanish veterans - like Santiago Canizares, David Albelda, Ruben Baraja, Miguel Angel Angulo and Fernando Morientes - with their best days well behind them, plus young hopefuls and misfit foreigners.
The young hopefuls, led by internationals Raul Albiol and David Silva, are generally failing to fulfil their potential.
The foreigners, meanwhile - particularly German goalkeeper Timo Hildebrand - look ill at ease and unsure of themselves, as if they are beginning to wonder whether they have come to the right place.
One reason for the general unease of the players is the club's appalling injury record in the past two seasons, with no less than eight knee ligament operations having to be performed.
Soler has changed the club doctors several times, after criticism from injury victims like Brazilian midfielder Edu, Baraja and winger Vicente Rodriguez.
Another obstacle for Koeman will be the attitude of the fans in the Estadio Mestalla.
The "valencianistas" are notoriously critical of their own team, and quick to jeer and whistle when things start to go wrong.
Koeman will now have to serve up a more attractive fare than that offered this season by PSV Eindhoven, the workmanlike team which he led from July 2006 until Wednesday.
Koeman is clearly not afraid of a challenge. He proved that when taking over sleeping Portuguese giants Benfica in 2005.
But he will need his courage, not to mention experience and intelligence, to revitalize a Valencia squad that has been going downhill since 2004.
DPA