* Cheaper to put telecoms&DC facilities out of expensive areas

* Little benefit from landing in the urban area

* Cities often have extra regulatory requirements

* Higher risk of cable breaks if you are in an area with lots of development or in a river with dredging

As others have mentioned, the more you get close to a population center the more activity is happening, even underwater in rivers.

Anchors are being drug, there are other already existing lines, it's all quite complicated.

If you have a fatpipe already running OUT of the city center, it can be much easier to join up to that elsewhere, and then dip into the drink.

In the US there are quite a few landings just outside of NYC and LA. I'd guess London is too far inland, and it's cheaper to run fiber over land.

There is probably also an incentive to keep the cables away from major shipping lanes where they'd disrupt the ability for ships dropping anchor. Notice around Seattle some cables snake up and through the sound, but it's also extremely deep water. That landing is also far north of the city proper, so any ships waiting near port are a ways from the landing site.

The CLION terminates in Rostock which is quite hit and near a river, called Warnow.

https://www.submarinecablemap.com/submarine-cable/c-lion1