We've not seen many, but they're easy to identify by their distinct tan fatigues.

There are few differences between this uniform and the Colonial Fleet fatigues, so please refer to that guide for the basics.
So what's different? Obviously the Marines use tan fatigues with brownish suede and webbing. There's one other slight difference. Whereas the webbing on the pockets and cuffs of Colonial Fleet fatigues features fastex buckles the Colonial Marines have cam buckles.


That's really the only difference, those buckles and colors.
If you're ready to stand out as a Colonial Marine, here's what you need:
-Tan fatigue blouse (four pocket suggested)
-Matching fatigue pants - 6 pocket
Can be found at military surplus, or online.
-One yard of tan 1" nylon webbing/strap, horizontal weave
Can be found at military surplus, or online.
-Four 1" cam buckles
Military surplus, or online.
-1.5" tan nylon web belt w/fastex buckle
A suitable one online. (Site is great for this uniform)
-SWAT style boots
Available at military surplus, or various online stores
-Battlestar Patch
Patchgeeks or eBay.
-Tan suede, at least a square foot
Tandy's or other fine leather stores (*Microsuede or Ultrasuede are good alternatives and can be found at your local fabric store - Dan K.)
-Rank insignia
Coming soon to Quantum Mechanix.
-Undershirts, gray muscle shirt and charcoal gray tank top
Yet to be positively identified, likely custom.