Q: What kind of shoes should I wear when in Ihram?
A: You should wear your most comfortable pair of sandals. The sandals should leave most of the foot exposed such as the heal and toes with the exception of the straps used to hold them in place.
It is also permitted that the sandals be constructed of any permissible material even if they are sown together.
Wearing shoes which over the foot and the ankle are impermissible.
Wearing shoes/clogs which cover most of the foot excluding the ankle should also be avoided as they too are considered impermissible.
Source: Hidayat al-Raghib w/explanatory notes from Dr. M. Jasir