I recommend that any pants considered for walking the Camino be fairly loosely fitted, with plenty of room to move and bend, and have the following properties:
Material - 100 % nylon or similar synthetic cloth as it dries FAST and does not hold stains. Ideally the material should impart some UV protection too, but that is secondary to utility.
Colour - Recommend olive and medium to charcoal grey, and possibly a dark khaki. Black and white show too much grime and stains. You are not on a fashion parade.
Design - Lower pants legs must zip off. The better designs have TWO zips (See REI's "Safari" model pants); one zip to open the leg top to bottom, and another running around the leg. This setup precludes having to remove your boots. Also, the lower pants legs can be laundered separately or more often as needed. This obviates the need for gaiters most of the time.
Features -
- More belt loops are better than fewer; seven are better than five...more loops support LOADED pants weight easier and are less likely to tear as the weight is spread among extra stress points. I also use nylon "keepers" to fasten my rucksack waist belt to my pants belt at the front in two places to stop the pants from sagging and dragging in the mud - I HATE MUD!
- Belt loop width should support using a 38 mm (1 1/2 inch) nylon web belt. Most money belts are either 32 or 38 mm wide ( 1 1/4 - 1 1/2 inch). I use a brown, nylon, webbed money belt that is 1 1/4 inch wide (@32 mm).
- Waist fastening buttons are better than snaps; and a double closure, internal button or hook with exterior snap is typical.
- More pockets are MUCH better than fewer pockets. My REI "Safari" slacks are three years old and have been redesigned in recent years. The older design had more protected, zippered pockets for valuables and emergency medication like aspirin to treat a heart attack, or an emergency stash of my personal medications.
- Deeper side cargo and side hand pockets are far better than shallower pockets. Try to find a pair of pants with cargo pockets deep enough to hold a Brierley Camino guide (for example), at least far enough to preclude it easily falling out of the pocket. Side cargo pockets should be at least deep enough to hold a smart phone, passport and your pilgrim credential in a sturdy zip lock bag. For bags that will hold most mobile phones, pilgrim credentials and national passports, see:
https://loksak.myshopify.com/collections/aloksak/products/aloksak-2
They are available at many outdoor stores too. I have seen them at AS Adventure in Belgium and Decathlon in Spain.
- Button fastening side cargo and rear pockets are superior to velcro IMHO. Velcro patches work loose, but buttons are easier to repair and replace if need be. My slacks have velcro but I wish they had buttons.
- Pants need not be a heavyweight material. Thin synthetic material is sufficient. I usually walk in April and May, and have encountered snow at elevation many times. As long as you keep your torso, head and feet dry and warm, you will be fine.
I regard pants as part of my overall load carrying system and solution for a Camino. I assess them accordingly. All year long, between Caminos, I am on the lookout for something that will improve over my REI "Safari" model slacks from 2013. I have yet to find something better. If anyone has a constructive suggestion, please share it.
As an FYI, in April 2015, I walked the Porto to Santiago route wearing 5.11 brand tactical slacks, saved from when I was working. Even though they were the lighter, rip-stop cotton-poly blend they did not work as well as the REI pants. They were heavier, hotter, and slower to dry. Arguably, they were much "tougher." However, on the Camino, IMHO one is trying to reduce weight and maintain modesty. All else is secondary. Function is primary to fashion. Having the right item immediately close to hand in a crisis could prevent injury or even save a life. It certainly enhances the Camino experience to be able to bring a digital camera to bear quickly, or be able to access a mobile phone if you should need to dial 112 in an emergency.
I pack and load everything to follow that rule. The rucksack ONLY comes off my back at a formal rest stop or at the end of the day. I intentionally arrange everything I carry and how I carry it to maintain that profile. Everything I might need during the day while walking is attached to the FRONT of my harness or on my person, IN MY WELL-THOUGHT OUT PANTS.
I hope this helps.