by foot or on foot

[arjana]

Hi
I'm a newbie here, and I apologize if this question has already been answered.
It's about the difference between by and on foot. My students tend to use by foot and I keep correcting them. Now I'm not so sure about it any more.
What should I tell them?
Thanks
arjana

[BobK]

I've never met a hard and fast 'rule', but my usage agrees with your correction: by or on a...] car/plane/bike but on foot - and 'on Shanks's pony' (an idiom that means "on foot"). However, there are so many more by options that it's easy, and tempting im many contexts - especially in lists - to say "by foot".

b

[Horsa]

There is a rule though and the correct usage is 'on foot' 'on horseback' and 'by' almost everything else.