The rule
Official hospitality facilities at the Championships apply a smart dress code and enforce it at the door of the facility, not the gate of the ground. That distinction catches people every year: you can be perfectly dressed for the queue and refused entry to lunch.
Men
A jacket, a collared shirt and tailored trousers. Ties are welcomed in most facilities rather than required; in the more formal ones they are expected. Smart loafers or leather shoes.
Not acceptable: sportswear of any kind, denim, shorts, trainers, T-shirts. A linen jacket is fine; a jacket over a T-shirt is not.
Women
Smart day dress — a dress, a skirt or tailored trousers with a smart top. Hats are welcome but not required. Sandals and wedges are fine; flip-flops and trainers are not.
Not acceptable: sportswear, denim, shorts, anything that reads as beachwear.
The English July
It rains, then it is hot, then the sun goes behind the roof. Bring a layer you can carry. An umbrella is more useful than it looks and less useful than a jacket.
If you are on Centre Court in the Royal Box
Different rules apply and you will have been told them. Jackets and ties for men are required; smart dress for women, no hats that obstruct the view behind.
Hospitality at Wimbledon is sourced through official programmes; the provider invoices you directly and nothing is added by us. How Wimbledon hospitality works.