Short answer. When a private person enters another's dwelling against the occupant's will. No damage or theft is needed — the unwanted entry is the crime. The penalty rises if violence or intimidation is used, and the current fines come from Republic Act No. 10951 (2017).
What the law says
If the offense be committed by means of violence or intimidation, the penalty shall be prisión correccional in its medium and maximum periods
Revised Penal Code, Article 280 — Qualified Trespass To Dwelling. Read the full provision →
The elements, in plain terms
Three things must line up. The offender is a private person — a public officer who enters improperly is dealt with under a different provision. The place entered is a dwelling, meaning a place used for rest and privacy, which includes a rented room, an apartment or a house's enclosed yard, and does not depend on who owns it. And the entry is against the will of the person who lives there. That last element does not require a shouted refusal. Opposition can be shown by a locked gate, a closed door, an earlier warning to stay away, or the plain circumstances of the entry, such as coming in through a window at night.
Nothing else has to happen
Readers usually search this after someone walked into their home during an argument, a debt collection, or a family dispute, and want to know whether it is "really" a crime when nothing was taken or broken. It can be. The offence is complete on the unwanted entry itself. Conversely, entry that begins with consent is not this crime, even if the visitor later behaves badly — refusing to leave when told to go raises different questions. Consent given by any lawful occupant generally suffices, which is why disputes between separated spouses or co-tenants over who let a person in are so common.
The exemptions written into the article
The Code expressly carves out three situations. It does not apply to a person who enters for the purpose of preventing some serious harm to himself, to the occupants, or to a third person — so breaking in to stop a fire or reach someone screaming inside is not this crime. It does not apply to a person entering to render some service to humanity or justice. And it does not apply to anyone entering cafés, taverns, inns and other public houses while these are open, because those are not dwellings in the protected sense during business hours. Each exemption is fact-driven and cannot simply be asserted after the fact.
Penalties today, and how a case starts
A simple entry against the occupant's will carries arresto mayor and a fine not exceeding two hundred thousand pesos. Where violence or intimidation is used, the penalty rises to prisión correccional in its medium and maximum periods, with a fine not exceeding the same amount. Those peso figures are current because of Republic Act No. 10951, enacted in 2017, which revised fines and property values throughout the Revised Penal Code; sources still printing the 1930 amounts are out of date. If it happened to you, report it promptly, note who witnessed it, and preserve any camera footage before it is overwritten — footage is usually lost within days, and it is often the whole case.