Madam Malkin's is a clothing shop next to the bookstore, Flourish & Blotts. It sells robes and other clothing, including the standard Hogwarts-required plain black work robes, and dress robes. Madam Malkin, a squat witch who wears mauve robes, and her assistants will tailor the robes to fit right in her shop. Malkin is an archaic term for a crotchety old woman.

The Apothecary sells potions and potion ingredients. The shop is "fascinating" despite its very bad smell — a mixture of bad eggs and rotten cabbage. The inside includes barrels of slimy stuff on the floor; jars of herbs, dried roots and bright powders on the shelves; and bundles of feathers, strings of fangs and snarled claws hanging from the ceiling.

The Cauldron Shop sells all different varieties and sizes of cauldrons, including copper, brass, pewter, silver, self-stirring, collapsible, and solid gold. Hogwarts requires its students to have a size 2 pewter cauldron. The Cauldron Shop is very near to the entrance from The Leaky Cauldron.

The Daily Prophet Office is the office of the wizarding newspaper, The Daily Prophet, as witnessed by the fact that "Letters to the editor should be sent by owl to The Daily Prophet, Diagon Alley, London." It should be noted that there is an Evening Prophet and Sunday Prophet.

Eeylops Owl Emporium sells owls and supplies such as owl treats. The inside is dark and full of a low, soft hooting, rustling and the flickering of "jewel-bright eyes." Among the types of owls sold are Tawny, Screech, Barn, Brown, and Snowy.

Florean Fortescue's Ice Cream Parlour, under the management of Florean Fortescue (founder and shopkeeper), sold ice cream, including sundaes, which could be enjoyed at outdoor tables.

Flourish & Blotts sells a great variety of magic-related books, including textbooks for Hogwarts courses and other books of general magical interest. In the back there is a corner devoted solely to Divination, which includes a small table stacked with titles like Predicting the Unpredictable: Insulate Yourself Against Shocks and Broken Balls: When Fortunes Turn Foul. Another small display contains the book Death Omens: What to Do When You Know the Worst is Coming. There is usually a display of gold-embossed spell books the size of paving slabs in the window.

Gringotts is the only known bank of the wizarding world and it is operated primarily by goblins. A snowy white building, near the intersection of Knockturn Alley and Diagon Alley, Gringotts towers over all neighbouring shops. Customers pass through a set of bronze doors and then silver ones before entering the lobby. The main floor is paved with marble and has long counters stretching along its length. Within, Wizards and witches keep their money and other valuables in vaults that are protected by very complex and strong security measures. The vaults extend for miles under London and are accessible through rough stone passageways and then by means of magic carts that travel speedily along their tracks. Gringotts also offers Muggle-Wizarding currency exchange.

The Leaky Cauldron is a pub and inn for wizards, located on the Muggle street of Charing Cross Road in London, offering food, drinks and rooms to rent. It was founded by Daisy Dodderidge (1467–1555) in 1500 "to serve as a gateway between the non-wizarding world and Diagon Alley." On the main floor, the inn has a bar, several private parlour rooms and a large dining room for guests to dine. On the upper floors, there are a number of rooms available. People often stay at The Leaky Cauldron when they come up to London on shopping trips; there is no mention of other wizarding hotels or inns in Diagon Alley. The pub serves as a way of entering onto Diagon Alley from the Muggle London either for Muggle-borns and their Muggle parents. The rear of The Leaky Cauldron opens onto a "chilly little courtyard" where a brick is tapped three times.

The Magical Menagerie is a magical creature shop that, besides selling magical creatures, also offers advice on animal care and health. The shop is very cramped, noisy and smelly, due to every inch being covered with cages. Among the creatures in the Magical Menagerie are enormous purple toads, a firecrab, poisonous orange snails, a fat white rabbit that can turn into a silk top hat and back, cats of every colour, ravens, Puffskeins, and a cage of sleek black rats that play skipping games with their tails.

Quality Quidditch Supplies sells broomsticks and Quidditch-related items. The store windows often draw young customers to gaze longingly at the products.

Twilfitt and Tatting's is a wizarding clothing shop located in Diagon Alley.