At Maasai Mara the dress code is fairly informal; just pick the clothes that you are most comfortable in.
In the Maasai Mara you are at about 1300-1500 meters above sea level, so nights can be a bit chilly. Bring your sweater or fleece jacket and wind or rain coat as well. Morning and evening game drives can be quite cold.
The savannah is dusty, so white clothes are not advisable. Sandals are fine within the camp, but gym shoes – preferable with a solid sole – or hiking boots are important for walking safaris. Bring a small backpack to carry your water bottles, notebooks, binoculars etc.
If visiting Lamu we strongly encourage covered shoulders and knees when in Lamu town or Shela Village, out of respect for the locals’ religion and culture. When you are on the beach or at the Dhow, bikinis or bathing suits are fine.