Can wellies substitute hiking boots for travel?

This is of course up to you, but I would consider a few things. First, wellies are HEAVY. A nearly 10 mile hike with that amount of weight will feel like doing double the miles. Second, your feet will get much more hot and sweaty, likely leading to more blisters and discomfort than wearing even just tennis shoes. Based on my quick read of the trail description, unless it's raining buckets you are unlikely to get wet feet - you won't be forging through deep water at any point on the hike. I personally don't need high top boots for a day hike like this - unless you are prone to ankle injuries, a sturdy set of shoes will get you there. There are vast options for truly water proof hiking shoes that are not high tops (see sample here) and are much more comfortable.

I think you need to ask some outdoorsy Brits. I know my daughter and her husband (and family) would go everywhere in their Wellies. We'd be out for the day, wandering through parks, woods, muck, rain, etc. Our wanders lasted all day (with pub stops) and I'm sure we regularly went over 10 miles. They used them in London parks and in the Dales. I never heard any complaints by them and I had wished on several occasions I had my own. A quick skim of the walk you described does involve some wetter lands, should you choose to take that route (the fisherman's route). My question is what the weather is in Poland compared to the UK at that time of year, as it will reveal how wet the environs will be or if it will rain while you are walking. Well insulated Wellies are comfortable, so maybe you want the insoles. I know my daughter liked hers fleece lined.

During really wet and muddy conditions, I've comfortably logged thousands of miles in Xtra Tuf boots. So, if your Le Chameau boots are similar and your feet really prefer staying dry, give 'em a go.

Quite a diversity of opinions here. I am going to agree with CL and MrsEB and say that Wellies are not suitable for a hike like this, no matter how comfortable they seem when you wear them around for an hour.

This is a ten-mile hike with 1500 feet of elevation gain. It is in the mountains of British Columbia ( not Poland). According to the description, there is one creeknnear the beginning and the rest of the trail is dry. They do not say how one crosses that creek---bridge, log, hopping on rocks, or wading. Only in the last case will the water touch your feet. I can walk through a small creek in mynGore-Tex hiking boots and long as the water is not deep enough to come over the tops, my feet stay dry. If that one creeks is why you think your feet will get wet, you could carry a light pair of water sandals and use those for the ford.

If it is raining hard enough to soak your boots will you actually do the hike?

What would concern me is the elevation gain. On the steep uphill sections, if your foot is not held securely in place by the boot, your heel can slip up and down as you walk, practically guaranteeing a blister. A properly-fitting trail shoe or boot that laces up will prevent this.

And on the downhill, if your foot is not held securely in place, it can slide forward and your toes may hit the front, which is very uncomfortable. Again, properly-fitted hiking shoes or boots will prevent this. Indeed when you gomtomget fitted the salesperson should check to make sure this will not happen.

Another problem with Wellies for hiking is that they do not breathe. This will cause your feet to sweat on a warm day, which is another guaranteed blister if it goes on long enough. Adding Sorbothane insoles may just make it worse, if those are anything like the Sorbothane insoles I bought ( a mistake, and now I only use them in winter). Hiking shoes and boots these days are highly breathable----even the Gore-Tex ones.

For many years, friends and myself have used the boots I mentioned above to climb safely and comfortably a very large number of mountains (up and down). Go figure.

As I said, there is a diversity of opinions here. Xtra Tuf boots are designed for Alaska fishermen---and I know they are the " gold standard" for that purpose and also recommended by some of the SE Alaska tour companies and small ship cruise companies for visitors. But they make no claims on their website to be good for hiking. If they have worked out for you and your friends, that is great. But frankly, as a hiker, backpacker, and ski mountaineer for the last 50 years, I have never seen anyone hiking in real mountains in such boots, nor would I try it myself.

Lola notes "Another problem with Wellies for hiking is that they do not breathe. This will cause your feet to sweat on a warm day...."

Your feet can even sweat on a cold day. My Garmont ski touring boots are plastic (no seams) with thermal fit liners. It's a good thing the liners can be pulled for drying at the end of the day because the boots do not breath. Even skiing at below freezing air temperatures, I can pour out moisture from the plastic shells after I pull the liner for drying.

I hope you use wool or synthetic socks that will absorb moisture if you chose to use non-breathable boots. Carry a spare pair or two of socks for mid-day changes during rest breaks.

Felt insoles combined with wool socks work like a champ for me.

The only "Poland Lake Trail" I could find is the one Lola mentions. South Central BC Cascades does not seem to be bog and moors country and snow should be pretty much gone except for very high north exposure zones by September.

http://www.env.gov.bc.ca/bcparks/explore/parkpgs/ecmanning/poland.html

Step over the creek bed, which is dry in the summer but full of water
in spring and early summer....

Plus, Wellies are seriously heavy to pack if you are flying to Canada ( can't tell where you live). not something I would want to wear on the plane either.