KSA has changed enormously, and in many ways, over the last few years. The underlying modesty in dress and behaviour remains more or less intact, but the religious police were disbanded some years back. While some younger people may be testing boundaries, in general covering legs, shoulders and upper arms would be wise and earn you respect. No need to cover the head, though you might need a sun hat for other reasons.

But you will see many local women in elegant abayas - the open/closed floor-length cloaks, some of them with the niqab (the veil that covers the lower part of the face) or a head scarf/hijab: some women favour the burqa outside their home (this is the complete head to toe covering with most of the face hidden). You won't be expected to dress in any of these ways or adopt any of the hair or face covering.

For the more tradtional, there remain well understood protocols which establishes who (male) can see the face of which female friends and relatives. To make life easier, some restaurants provide areas for mixed groups and families, often at curtained off tables. If you find yourself in one of these places with "family rooms" it's probably a good idea to take up the offer.