Buying property off-plan simply means that you secure your property purchase before it is actually built. There are several advantages to buying Spanish property in this way:

In a rising market like the Murcia property market, it normally means that you pay a cheaper price than somebody who buys a similar property in Murcia on the day of completion.

In popular developments in particular golfing resorts there is often a rush to secure the best units on the best developments, so by buying off-plan you can normally secure the property that you really want, rather than what is left, the homes with the best locations, views etc.