Most soap dishes are built into a recess in the tile. For those who need to add a soap dish, there are two options available. The first is to drill holes, the second is to use epoxy. Of the two options, epoxy is a faster solution, but may not be as permanent as screw-type fasteners.
Mounting the Soap Dish Using Epoxy
This method is very straight-forward. Avoid using too much epoxy, and allow the soap dish to cure into position for at least 24 hours after application. Note that ordinary adhesives probably will not be sufficient to bond the soap to the tile, and an actual mixed epoxy may be required to provide a dependable chemical bond.
Mounting the Soap Dish Using Screws
Before you can attach a soap dish to tile, drill pilot holes which are slightly smaller than the shaft of the screw. Avoid drilling into the grouted seams between tiles, and hold the drill steady to avoid damaging the tile. Alternately, slightly larger holes may be drilled, and ordinary hollow wall mounting inserts placed in the holes before attaching the screws. Mounting inserts are available at any hardware store.