The Spanish Navy's Combat Supply Ship Cantabria will operate from Australia, February to November 2013. There are five ships designed by the Spanish company Navantia, to be delivered to the the Royal Australian Navy in the next few years: two Canberra class Landing Helicopter Dock Ships and three Hobart class destroyers. This makes the deployment of Cantabria, which was also designed and built by Navantia, a useful exercise for the RAN to get used to Spanish ships.
The RAN will also need new submarines to replace six Collins Class boats. Assuming the Navantia vessels under construction work well, a low risk option would be to buy submarines from the same company. S-80 Class Submarines, are now under construction by Navantia, for the Spanish Navy. This may not be the most advanced submarine available and has a shorter range than ideal for Australia, but would be affordable and have a reasonable chance of operating reliably. The first few boats could be built in Spain and later ones in Australia.