You can easily reach Sardinia through the airports of
Alghero [North West] - www.aeroportodialghero.it
Cagliari [South] - www.sogaer.it
Olbia - [North East] - www.geasar.it
Especially from April to October, all airports are well connected with some of the main cities in Uk, Germany, France,Spain, Norway, Sweden and other countries in Europe.
These some of the national and international companies arriving in the three airports on the island:
Easy Jet, www.easyjet.com;
TUI fly, www.tuifly.com;
There are numerous ferry services from the Italian mainland to Sardinia: from Genova, Livorno, Piombino, Civitavecchia and Napoli
An overnight crossig usually takes between 10 and 12 hours.
A daylight crossing can take as little as 5-6 hours but most of the crossing are overnight.
Moby Lines (www.mobylines.com/cms/export/en/index.html)
Which route or company is most convenient depends on where you are in Italy.