Hi,
I had written a response yesterday that Explorer ate up and I was saying that I hoped Loredana would chime in and here she is :D
Anyways ... if you want to dive the Haven, you can use
techdive they are located in Arenzano and the ride to the Haven is very short, just 900m !
The dives in Portofino, which is 45 min by car from Arenzano, offer plenty opportunities of rec sites with pretty Mediterranean fishes.
If you cave dive, you are approx 1h30 hours from the best cave diving in Italy. The caves are located in Val Stagna, close to Vicenza.
Take care
Cris