Those who skipped Kuta or Cairns these holidays would do well to head to Beaumaris in the south-east of Melbourne.

That was where Summer by the Sea, a festival of largely free coastal activities, was launched on Wednesday by state Environment Minister Ryan Smith.

More than 300 events are scheduled statewide until January 26. These include snorkelling, kayaking, beachcombing and yarns with rangers.

''I'm blown away by the diversity we have here in this state, and how much of it is public,'' said Mr Smith, as he joined a rock-pool ramble at Ricketts Point.

In an iPad era, Mr Smith said hands-on exploring was more important than ever.

''How can you get kids to care about the environment when they don't know anything about it?,'' he asked.

Part of the answer is Ray Lewis. The 76-year-old moved house three years ago to be closer to the volunteer-run group, Marine Care Ricketts Point.

''I was a pretty hard, military, right-wing, public-company chairman, high-tech entrepreneur,'' he said. ''But I appear to be getting softer as I get older.''

These days the former air-force navigator can be found holding shells aloft for wide-eyed visitors, and sampling the salty grass Aboriginal people are believed to have used to season kangaroo meat.

Some days out diving, he said, you can't see anything for all the teeming shoals of fish.

''Underneath, the rocks are like cathedrals, with the colours of ascidians, corals and coralline algae - reds and greens and bright yellows. They are just breathtakingly beautiful,'' he said.

Ricketts Point was declared a marine sanctuary in 2002, and the three kilometres of coastline that is just south of Royal Melbourne Golf Club is beginning to thrive.

After a slow start, fish biomass has increased tenfold in the last three years. ''It's one of the best kept secrets in Melbourne,'' said volunteer diving instructor Michael Letch, as he surveyed a solitary family frolicking by the shore.

''On a day like this in the south of France, there would be a hundred thousand people here. We have got it so good.''