Sputtering from tungsten under simultaneous bombardment with C and O ions, as well as D ions, is investigated using a Monte Carlo simulation model which combines dynamic composition change in the surface layer with transport of sputtered atoms in a scrape-off layer (SOL) plasma. The implantation of C ions causes a lowering in sputtering of tungsten and an additional sputtering of implanted C. With increasing ion fluence, the sputtering yield of tungsten (implanted C) decreases (increases) due to formation of a carbon rich layer near the surface. By simultaneous bombardment with D, C and O ions, the tungsten surface is eroded due to sputtering of implanted C by D ions as well as O ions, whereas a thick carbon layer is formed if no sputtering by D and O ions is included in the simulation. The redeposition of sputtered atoms during their transport in the SOL causes a decrease in the low-energy component of the energy distribution, which results in a considerable decrease in the net sputtering yield, particularly for tungsten. The redeposited atoms acquire heavier masses and lower charge state, as well as lower energies.