Hi I'm new to tis forum and hope that some one can help me with this.

I will be working on the ship and have the privilege of having a guest with me (which is extremely rare)

I would like to bring on my Thai partner (we're not married) but would he need a visa?

The point of embarkation is Barcelona and it will cruise around Europe including Italy, Spain, Monaco, Portugal, England, Ireland, Germany, Sweden, Finland, Russia and Denmark. Some stops are 2 nighters.

Your employer should know that question. As he needs to come on board the ship, he certainly would need a visa for Spain (Schengen). Oher countries might depend on if he wants to leave ship or not.

Yes, he would need a visa for every port of call that he intends to disembark, with the exception of, I think Russia.

So at least a UK and Schengen Visa, I don't know if there is a special visa for cruise passengers.

He will need a Schengen visa issued by the country where he will enter Schengen ( Spain in this case), or where you will spend the most time. You will need to provide an itinerary showing where the cruise will be stopping in order to get the visa. The Embassy, of whichever country, may insist on a confirmed reservation for the trip.

The UK and Ireland ( Irish republic ) are not part of the Schengen area. He wil need separate visas, one for UK and one for the Republic of Ireland.

If they cosider him as crew rather than passenger other rules may apply. Better check with the company as to his ship's status.