NOOOOO, they do NOOOOT! The arch is high enough, but too soft so doesn't support the bones at all.
I love Crocs, but only for resort or around the house/yard. They feel great after a day of being on your feet, but if you have plantar fasciitis, stick with the shoes your podiatrist recommends!
I had 2 1/2 years of suffering with plantar fasciitis, and bought Crocs on the recommendations of so many on these boards. At first I thought they were a miracle, a wonder...they felt so good! So I started wearing them to work...and my feet felt great for day 1, not so great on day 2, then actually worse on day 3. I asked my podiatrist about them, and he said that the arch was too soft, and my weight was very quickly breaking them down. Also, he said they have no lateral support, which if you overpronate, means your gait is unsupported.
If you have no problems going barefoot, these are really fun, comfy shoes. If you need your gait/arch/foot supported in any way, they are NOT a miracle cure!
By the way, my PF finally resolved itself, with cortisone shots, corrective orthotics, and weight loss. I wear Keen Montereys in the parks when I'm not wearing my orthotics, and they were absolutely wonderful!