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.

Some of the ingredients available are silver unicorn horns (for twenty-one Galleons each) and glittery-black beetle eyes (five Knuts a scoop). Both of these are basic Potions ingredients for Hogwarts students.

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

Eeylops Owl Emporium sells owls and supplies like 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, the founder and shopkeeper, sold ice cream, including sundaes, that could be enjoyed at outdoor tables.

Flourish & Blotts sells a great variety of 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 spellbooks the size of paving slabs in the window apart from the time they brought many copies of The Monster Book of Monsters

Gambol and Japes sells practical joke and trick items including an all time favourite; . Filibuster's Fabulous No-Heat, Wet Start Fireworks.

Gringotts is the only known bank of the wizarding world and it is operated primarily by goblins. Wizards and witches keep their money and other valuables in vaults that are protected by very complex and strong security measures. Gringotts also offers Muggle-Wizarding currency exchange.

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. The vaults extend for miles under the city and are accessible through rough stone passageways and then by means of magic carts that travel speedily along their tracks. The inscription on the front door reads:

Enter, stranger, but take heed
Of what awaits the sin of greed
For those who take, but do not earn,
Must pay most dearly in their turn.
So if you seek beneath our floors
A treasure that was never yours,
Thief, you have been warned, beware
Of finding more than treasure there.

Madam Malkin's is a clothing shop next to Flourish & Blotts. It sells wizarding robes, including the standard Hogwarts-required plain black work robes, and dress robes. Madam Malkin, a squat witch known to wear mauve robes, and her assistants will tailor the robes to fit right in her shop.

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 gigantic tortoise with a jewel-encrusted shell, 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.

Ollivanders is a magic wand shop described as narrow and shabby, with a sign that reads Ollivanders: Makers of Fine Wands since 382 BC in peeling gold letters over the door. The only display is a single wand lying on a purple cushion in the dusty window and inside there are countless narrow boxes piled neatly right up to the ceiling.

Mr. Ollivander, the pale-eyed, white-haired shopkeeper, makes and sells magic wands to witches and wizards as they enter school or break their old wands. He remembers each and every wand he has ever sold. To determine the best wand for a witch or wizard, Mr Ollivander measures various body parts and then checks the reactions of various wands to the buyer, a process he refers to as "the wand choosing the wizard."

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

An 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.

The Leaky Cauldron is a pub and inn for wizards, 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." The current barman and innkeeper is Tom.

The inn also has a bar, several private parlour rooms and a large dining room for guests to dine. 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 rear of The Leaky Cauldron opens onto a "chilly little courtyard" just off of Diagon Alley, but the pub faces onto Charing Cross Road. As such, it is a means of passing from between Diagon Alley and Muggle London.

Twilfitt and Tatting's is an upmarket clothing shop. It seems to be used by the "Purebloods" more than others though.