Lots of words that are connected with the sea take “on” as a preposition. (Prepositions are little words such as in, at, for, of, from, above, etc.)

Let’s have a look at some:

Sea Words with On

You say on the beach.

On the sea

On the seafront (the seafront is the area of land next to the sea). You can also say waterfront.

On the coast

On the boulevard

On an island

River Words with On

Also river words tend to be with on:

On the river: The boat is on the river. The log is floating on the river. Paris is built on the river Seine.

On the shore

On the riverbank

So why do you sometimes hear IN the Sea?

Now you can also hear people saying in the sea or in the river. What’s that then?

In the sea is different from on the sea. In the sea means in the water, which actually means under the water, or at least partly underwater. When you’re swimming, you’re in the water. That’s why you say you’re swimming in the sea (or in the river or in the pool). Fish swim in the water. The tiger in the picture is in the water. But ships sail on the water, because you see most of the ship above water. A large part of a ship is actually in the water, but we don’t see that. So boats, ships, rafts, inflatable beds and surfboards etc. are on the water.

But confusingly, when the princess threw her ball in the pond, it was in the water. Even though the ball most probably floated on the water…

And when ducks are in the pond, they are swimming in the water. Even if like with boats we actually see most of the duck above water.

Confusing? Yes, I know.

Now, try the exercise and try not to think too deeply:

Exercise

Choose a preposition (on or in).

You do this quiz online here.

1 The buoy is floating ____________ the water.

2 The most expensive houses are _____________ the seafront.

3 London is _______________ the River Thames.

4 We explored Alaska ______________ a cruise ship.

5 There are some amazing koi fish swimming __________ the pond in front of their house.

6 They were making a fire ___________ the beach.

7 The famous painting “A Sunday Afternoon on the Island of La Grande Jatte” shows people relaxing ___________ the banks of a sunny lake.

8 When we were on our safari, we saw hippos ___________ the water. Only their eyes were visible.

9 It’s fun to float your rubber boat _____________ on the lake.

10 The sea is rough. The swimmers are fighting not to drown _______________ the waves.

Want to do more quizzes about prepositions? Have a look here:

In or On 

In/On/Under 

At, in, on — Place

At, in, on – Time

Prepositions after Care