Do Muggles have to know a pathway/portal exists at Platform 9 3/4 to pass through it or can they just go through accidentally?

  • 2
    – Valorum
    May 12, 2018 at 8:28
  • Why would Muggles attempt to wall into a seemingly solid wall? May 12, 2018 at 9:54
  • 2
    @TheDarkLord E.g. they want to lean against the wall while waiting for the train.
    – TGar
    May 12, 2018 at 9:58

2 Answers 2


We can divide this into two parts:

  1. When the Hogwarts term is starting
  2. Other days

I would guess that if the Hogwarts term is not starting, the platform is closed. I don't have any proof, but given the care and caution, the wizards give about muggles, it sounds likely. It is also supported by the Pottermore quotation in the following part of the answer.

Conclusion 1:

In most of the days in a year, nobody can go through

When the Hogwarts term is starting, it is not that clear.

To cite Pottermore:

There are usually a number of plain-clothed Ministry of Magic employees on hand to deal with any inconvenient Muggle memories that may need altering at the start and end of each Hogwarts term.

I.e. if the muggles would go through accidentally, they wouldn't remember anything from that. So even in that case, it is not that dangerous.

I didn't find anything about that if they can go through accidentally. But there are common charms to repel muggles from something.

We know that from Mr Weasley (HP GoF, Chapter 8)

"Muggle-Repelling Charms on every inch of it. Every time Muggles have got anywhere near here all year, they've suddenly remembered urgent appointments and had to dash away again."

It seems very likely (as there is no reason against it), that some of them are used to this entrance.

Conclusion 2:

Probably, muggles don't try to go near to the entrance at all.

EDIT: I am reading Cursed child now and right in the first scene there is this issue mentioned:

GINNY: All you have to do is walk straight at the wall between platforms nine and ten.
LILY: I’m so excited.
HARRY: Don’t stop and don’t be scared you’ll crash into it, that’s very important. Best to do it at a run if you’re nervous.
ALBUS: I’m ready.

that’s very important
it sounds that in the case you are scared or stopping, you won't get through. Muggles don't have any reason to think they will go through or to run.

Final conclusion:

It is not possible to go through accidentally even if it is open and muggles are (mysteriously) near.

  • 3
    Dobby made the wall solid to prevent Harry from going to Hogwarts in Chamber of Secrets. It's been a while since I read the books, but if I remember correctly, they said something about Dobby closing it early, which would indicate that the wall is indeed solid for most of the year
    – Suppen
    May 12, 2018 at 12:57
  • @Muspelmegir I improved the answer based on the Cursed child.
    – TGar
    May 27, 2018 at 9:21
  • The first time Harry went through the barrier he was scared and thought he would crash, yet he still made it through.
    – Alex
    May 27, 2018 at 19:26

No one can accidentally go through the wall.

Muggles cannot accidentally go through the barrier to Platform Nine and Three-Quarters, because no one, including wizards, can go through it unintentionally. When Harry first attempts to go through it, he is told not to stop or be scared because then he’ll crash into it.

“Yes,’ said Harry. ‘The thing is – the thing is, I don’t know how to –’

‘How to get on to the platform?’ she said kindly, and Harry nodded.

‘Not to worry,’ she said. ‘All you have to do is walk straight at the barrier between platforms nine and ten. Don’t stop and don’t be scared you’ll crash into it, that’s very important. Best do it at a bit of a run if you’re nervous. Go on, go now before Ron.”
- Harry Potter and the Philosopher's Stone, Chapter 6 (Platform Nine and Three-Quarters)

Therefore, since it is required for even wizards who know about the platform to not be hesitant when going through the barrier, Muggles who don’t know there is one and happened to lean on the wall will not accidentally fall through.

But Muggles can go through it intentionally.

However, it is possible for Muggles to go through the barrier to Platform Nine and Three-Quarters if they do know it’s there and are intentionally trying to go through it. Lily’s parents and sister, all Muggles, were at the platform with her, so they all would have had to go through the barrier first.

‘I don’t – want – to – go!’ said Petunia, and she dragged her hand back out of her sister’s grasp. ‘You think I want to go to some stupid castle and learn to be a – a –’

Her pale eyes roved over the platform, over the cats mewling in their owners’ arms, over the owls fluttering and hooting at each other in cages, over the students, some already in their long, black robes, loading trunks on to the scarlet steam engine or else greeting one another with glad cries after a summer apart.”
- Harry Potter and the Deathly Hallows, Chapter 33 (The Prince’s Tale)

Therefore, it is possible for Muggles to visit the platform, but they have to know it exists first and go through the barrier intentionally.

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