I'm looking for some overshoes to keep my feet dry, warmth isn't too much of an issue – can anyone recommend something watertight and durable with a good seal at the top as I won't be wearing over-trousers?

need to go over MTB shoes (Specialized Comp), will mainly be used for commuting where main water comes in off the front mudguard and through the toe
wet feet don't bother me too much, but putting wet shoes back on at the end of the day is grim

You're probably better off looking at waterproof boots instead, every overshoe I've seen has a big hole in the bottom for the cleat and your Spesh Comps don't have waterproof soles so water will get in that way. I've also not seen overshoes with tight leg cuffs but they may exist.

endura mt500 over shoes are the dogs danglies. i've ridden the beast at c-y-b with these on during a very wet march earlier this year and when i took them off at the end there was just the smallest hint of damp on the inside of the overshoe(shoes were bone dry) after threeish hours of sploshing about in puddles.
think they cost about 25 notes.
think my shoes are spesh comps too.

Get some of these I have the previous versions (the MW01) and the keep my feet bone dry and for that price, you can't go wrong!

would prefer overshoes really for cost reasons and the fact that I may only use them a handful of times a year

I have the pro neoprene overshoes and they are jolly good. You just need to get a size bigger.

I use endura mt500 over shoes for my commute and yes they are good. But the rain will still rund down your leg and you end up with wet socks that way. If I waer my sidi dominators my feet do get a bit wetter than with shimano w101's and the overshoes.

You must be doing something special if your feet stay 'bone dry' for 3 hours in heavy ran, after a 1ish hour commute my feet start to get damp.

Overshoes can be better than winter boots on road for spray from front wheel. Boots off road all the way, but overshoes on road. I have some millenia old 'pro' cheapy numbers from yonks ago that are still doing the business. Wet coming up from the sole isn't such a problem and gaffa tape over any air ports your shoes may have on the sole helps big time.

Get thick rubbery ones, not slim crackly plastic ones. Make sure they have some reflective bits on and that when zipped up, they close nice and tight against your calf.

You must be doing something special if your feet stay 'bone dry' for 3 hours in heavy ran

My feet stayed dry for 6 hours into this ride earlier this year:

The roads were soaked and we rode through some very heavy storms. Old over shoes, speccy road shoes with the sole ports gaffa taped up, 2 pairs of merino socks. Toasty, even overly toasty.

(how many times do we think I can get that horrific pic up on here folks? 😉 )

So what did you wear to stop the rain running down your legs and wetting the tops of your socks, which by capillary action get the rest of your socks wet too?

Mudguards help to a certain extent but don't keep your legs dry in heavy rain/standing water.

My legs got soaking wet, but it seemed to run out the bottom over my overshoes rather than into my socks. They were a bit damp, but not wet. After 6 hours some found its way into the toe too.

I wasn't running a front guard, it takes ages to fit so it dosn't rub and clears the downtube. Which was stupid becuase I got litres of muck thrown back off the front wheel.

Overshoes can be better than winter boots on road for spray from front wheel

that's why my feet were getting so wet the other day – water coming off the mudguard was just soaking my feet through the mesh on the toe
those MT500s are looking like a good choice