There are many "Harry Potter" filming locations to explore in London and this gallery should help you identify some of them. You might also like to visit the Warner Bros. Studio Tour: The Making of Harry Potter.
The Leaky Cauldron
This is the entrance to the 'Leaky Cauldron' which is actually in Leadenhall Market. The building is on Bull's Head Passage, a small alleyway off Gracechurch Street on the side of Leadenhall Market.
Leadenhall Market was used as Diagon Alley and the entrance to the Leaky Cauldron in the first "Harry Potter" movie.
Leadenhall Market is a restored Victorian covered market designed by Sir Horace Jones in 1881 (also the architect behind Old Billingsgate and Smithfield Market). It was originally a meat market and you can still see the meat hooks above many of the shops but nowadays it's a great lunchtime destination with some fashion and gift shops too.
This is a short walk from The Monument if you fancy climbing the 311 steps for an excellent view across The City. Nearby you can find a not very well-known Viewing Terrace Near Tower Bridge to see Tower Bridge and HMS Belfast. These sites both feature in Harry Potter and the Order of the Phoenix.
St. Pancras Renaissance Hotel
The St. Pancras Renaissance Hotel was used as the entrance to King's Cross station in the "Harry Potter" films. Harry and Ron parked Mr. Weasley's Ford Anglia flying car in front of the hotel in "Harry Potter and the Chamber of Secrets" before returning when they couldn't get onto Platform 9 3/4.
This gothic masterpiece was originally designed by George Gilbert Scott and opened as the Midland Grand Hotel on 5 May 1873. It reopened as the St Pancras Renaissance Hotel on 5 May 2011.
King's Cross Station
To gain access to platform 9 3/4 to catch the train to Hogwarts, the young wizards had to run at a wall between platforms 9 and 10. When you visit King's Cross Railway Station you'll see that platforms 9 and 10 have a train line between them and not a wall. For filming, platforms 4 and 5 were renumbered 9 and 10 and this is where you'll find the hidden access to platform 9 3/4. To take a picture with a trolley in front of a platform 9 3/4 sign, find the Harry Potter Shop in King's Cross.
Ministry of Magic - Visitors Entrance
The Ministry of Magic was entered via a red telephone box in Harry Potter and the Order of the Phoenix when Harry and Mr. Weasley were going to Harry's hearing for using magic in front of Muggles. You won't find the telephone box here as it was only a prop for filming.
The location is just off Trafalgar Square. Walk down Northumberland Avenue or Whitehall and Great Scotland Yard is a road running between the two. Look for the junction with Scotland Place and you'll see the archway over Scotland Place but as this road was considered too short, filming was done on Great Scotland Yard and the archway over the road was added in line with the first lamppost (covering the doorway where the men are talking in this photo) and the red telephone box was placed in front of that, just before the first window.
Harry Potter and Mr. Weasley used Westminster Station in "Harry Potter and the Order of the Phoenix" on their way to Harry's hearing at the Ministry of Magic. Mr. Weasley had problems with his ticket when he tried to exit the ticket barriers.
Westminster is the station closest to the Houses of Parliament, Westminster Abbey, and a short walk across Westminster Bridge (also seen when Harry and the members of the Order of the Phoenix fly along the River Thames on their broomsticks) to the London Eye.
Gringott's Wizarding Bank
The interior of Australia House was used as Gringott's Wizarding Bank. Unfortunately, the building is not open to the public but ask the security guards nicely and they may let you peep through the door.
Australia House was opened by King George V in 1918 and is the home of the Australian High Commission so you can only go inside if you are visiting on official business such as dealing with visas, migration, and citizenship.
While in the area, do visit the London Roman Baths to see a bizarre National Trust property in central London.
If you're in the area on the weekend, consider a Somerset House Guided Tour or visit the Courtauld Gallery which is open all week.
This is the bridge where the Knight Bus had to squeeze between two London buses in "Harry Potter and the Prisoner of Azkaban." Please, do note the bridge actually has two-way traffic.
Lambeth Bridge is next to Westminster Bridge where you'll find the Houses of Parliament north of the Thames and the London Eye on the South Bank.
There is some uncertainty about the location of Grimmauld Place, the ancestral home of the Black family and the headquarters of the Order of the Phoenix between 1996-1997. But as number 12 can't be seen by Muggles we can accept this is the most likely location at Claremont Square (a short walk from King's Cross station).
Lincoln's Inn Fields was used as the street outside no. 12 Grimmauld Place in "Harry Potter and the Order of the Phoenix" .
Grimmauld Place is a wordplay on "Grim Old Place" and the Georgian buildings in the square, while well-maintained these days, could well have been much grimier in the past.
Leaky Cauldron Second Location
The filming location for the Leaky Cauldron moved from Leadenhall Market to Borough Market in "Harry Potter and the Prisoner of Azkaban." It was outside the doorway of this flower shop that the Knight Bus pulled up for Harry to enter the Leaky Cauldron.
The location can be found at no. 7 Stoney Street, under the railway bridge. Only the exterior was used for filming as the interior was filmed in a studio.
Next door, at 8 Stoney Street is the location of the Third-Hand Bookshop, a largely used bookshop supposedly on Charing Cross Road, where Harry met Gilroy Lockhart, his future tutor.
Borough Market is a popular film location and the area can be seen in "Bridget Jones's Diary," Guy Ritchie's "Lock, Stock and Two Smoking Barrels," "The French Lieutenant's Woman," "Entrapment," and others.
While in the area, after grabbing something to eat at Borough Market, why not walk around the corner and see the original location of Shakespeare's Globe Theatre on Park Street.
Reptile House at London Zoo
A scene from "Harry Potter and the Sorcerer's Stone" was filmed in the Reptile House at London Zoo during September and November 2001. In this scene, a Burmese Python spoke to Harry Potter.
In the 2009 movie "Harry Potter and the Half-Blood Prince," London's Millennium Bridge is used to represent the Brockdale Bridge that collapses following a dramatic attack by the Death Eaters. Thankfully this scene was created with special effects and the footbridge is still intact, connecting the City near St. Paul's Cathedral with the South Bank near Tate Modern.
Under the north side can be a fun place to go Mudlarking, a free activity for all of the family.
Lincoln's Inn Fields
Lincoln's Inn Fields was used as the street outside no. 12 Grimmauld Place in "Harry Potter and the Order of the Phoenix".
At Lincoln's Inn Fields you'll find Sir John Soane's Museum and the Hunterian Museum.