Who: The main characters in this scene are the people on the sampan in the foreground.

As far as I can remember, in most if not all the photos we have of sampans, it is a woman rowing. (While in the photos we have of western-style rowing boats, the crews are always men.) This photo follows the pattern, with a smiling young mother rowing the boat.

Her two passengers are presumably heading out to one of the larger boats in the harbour. The fishermen typically wore dark clothes, not lighter colours that show the dirt more easily. So perhaps the man at the front of the boat is visiting on business, or maybe he is heading back to a boat after attending some special occasion ashore?
 

What: The boat above the lady has two large baskets hanging off the back. They are two very different designs, so were they made for specific uses?

Several of the other boats are festooned with laundry, including a fancy three-level washing line on the boat in the distance (Update: JohnS notes the three-level line is more likely being used to dry fish). Must have been good drying weather that day!

Where: The postcard originally had this caption at bottom left, identifying the location as the harbour at Shau Kei Wan.

When: This is a Real Photo Postcard (RPPC), but as they were sold in Hong Kong from the 1920s through to the 1950s, it doesn't narrow down the date very much. 

Sometimes the back of an RPPC is pre-printed with details of the paper's manufacturer, and that can help pin down the date.

No manufacturer's details here though. Instead the paper looks to have been sold with a blank back, then the postcard seller used an inked stamp to add the text and the 'W H' stamp box. From the Hong Kong RPPCs I've seen, those with pre-printed backs were mostly produced before WW2, while those with stamped backs came after the war. Based on that, I'll guess the 1950s for the date this photo was taken.

If you can spot any clues in the photo that help identify the date, or if you have a mailed copy of this postcard with a postmark that shows a date, please let us know in the comments below.
 

Where: That's easy, with the Happy Valley racecourse clear to see above the trees in the foreground. At this time the centre of the racecourse was shared among several sports clubs, including the golf club. Those light-coloured shapes are the bunkers on the golf course.

When: Fortunately in old Hong Kong photos there is usually some building being either built or demolished, that can help us pin down the date the photo was taken. I can see two large construction sites in this photo, so we shouldn't have too much trouble.

As the Cenotaph recently had its 100th birthday, it's a good time to see what other buildings reached a major milestone this year.

50-year-old buildings:

The best known building on this list is Jardine House, or 'Connaught Centre' to give it its original name.

75-year-old buildings: