The Star ferries are a Hong Kong institution, like the Ding Ding (trams). I have never check which are older, but I'd put my money on the ferries because they could have run on steam. Alas they now use diesel motors.
The first route was between Hong Kong island at what is now called central and the tip of Kowloon at Tsim Sha Tsui. They added a service to Wan Chai later and have been plying these waters since. The route to central has become shorter over the years as the land area of central has built out into the harbour over the years. The Ding Ding no longer runs near the waterfront at this part of its route.
As I wrote in the Hong Kong introduction, I have the distinction of being one of very few people escorted off the lower deck Star ferry 25 years ago by the captain and crew. I had taken the ferry from central to Tsim Sha Tsui to take lots of photographs, and stayed on board for the return trip. But this is not allowed, the crew only spoke Chinese and I only spoke English so to get me off, the captain had to come and explain and march me off, even though I was happy to pay the sixpence fare. Happily they did not ban me from the ferry and I could enjoy traveling on it again and again on this latest trip.
When I was on board the second time, I had a most impressive stormy sky to photograph.