Upvote:2
Oman Air has an interlining agreement with Turkish Air, so they CAN transfer your baggage. https://www.omanair.com/gbl/en/alliances-and-partners
Whether they will, depends on how exactly your ticket was booked. Unfortunately if you book through a third party, that's always tricky.
- Check the first three digits of your e-ticket number and look up the airline code here http://www.kovrik.com/sib/travel/airline-codes.txt. That should either be 910 for Oman Air or 235 for Turkish. That would be your marketing carrier and the airline that's "responsible". If the code doesn't exist or is a completely unrelated airline, your number is probably not an e-ticket number.
- Go to both airline's website and put in your PNRs. See if they show up there. If your entire trips is visible, than it's a single booking and chances are good that your bags are checked through
- Call the airlines and/or lastminute and ask
Keep in mind that if your bags are NOT checked through, you may have to leave the transit area and you may have to meet all Visa and Covid requirements for entry into Oman.