Yau, Chi Wai Billy

Personal profile

Billy Yau has been a member of Wellington Chambers since being called to the Hong Kong Bar in 2015. He has a particular focus on criminal defence, and also accepts prosecution work from time to time.

His principal areas of practice encompass white-collar and financial crime, including money laundering, fraud, and corruption, as well as drug offences, regulatory and quasi-criminal prosecutions, and the full range of general criminal matters. He has particular experience in cases involving complex financial evidence, and in matters requiring close analysis of expert and technical evidence.

Billy appears regularly at all levels of the criminal courts in Hong Kong, from the Magistrates' Courts through to the District Court, the Court of First Instance, and the appellate courts. He is equally comfortable conducting trials, bail applications, mitigation, and appeals.

Fluent in both English, Mandarin and Cantonese, Billy is able to conduct hearings and prepare documentation in either language, and frequently acts in matters requiring bilingual advocacy.

A list of selected cases

HKSAR v Lam Yuk-kwan & Chan Ka-fung [2026] HKCA 989 (CACC 17/2024)

•  Acted for two of the appellants in the Court of Appeal on an appeal against sentence. The appeals were allowed and the sentences reduced, and the appellants were subsequently awarded the costs of their appeal.

HKSAR v Yau Yee-kei (HCCC 397/2023)

•  Acted as counsel in a High Court jury trial for the first defendant, charged with trafficking in a dangerous drug involving some 4,859 grammes of a substance containing 4,173 grammes of cocaine. Following trial, the defendant was unanimously acquitted (7–0) of trafficking.

HKSAR v Lam Chun-ho [2025] HKDC 1238 (DCCC 1218/2023 & 38/2024)

•  Acted for the second defendant on a charge of conspiracy to defraud and an alternative charge of conspiracy to deal with proceeds of an indictable offence (money laundering), arising from a telephone deception. Following trial, the defendant was acquitted of both charges, the Court applying the test in HKSAR v Harjani Haresh Murlidhar in finding that a reasonable person would not necessarily have believed the funds to be proceeds of crime.

HKSAR v Chau Hon-kwong [2024] HKCFI 120 (HCCC 92/2022)

•  (Led by Mr. Charles J Chan SC) Acted for the defendant on two charges of trafficking in dangerous drugs. Following trial, the defendant was acquitted of both trafficking charges and convicted only of the alternative charges of possession.

HKSAR v Kong Hin-fai [2023] HKCFI 279 (HCCC 27/2022)

•  Acted for the defendant on a charge of doing an act preparatory to trafficking in a substance believed to be a dangerous drug. Successfully persuaded the Court to adopt the lowest documented purity in assessing culpability, resulting in a substantially reduced sentence.

HKSAR v Chan Ka-yee [2026] HKDC 353 (DCCC 1497/2024)

•  Acted for the defendant on charges of threatened publication of intimate images, wounding, and criminal intimidation. Following trial, the defendant was acquitted of all charges after the credibility of the complainant's account was successfully challenged.

HKSAR v L.T.K. [2021] HKDC 1151 (DCCC 455/2020)

•  Acted for a young defendant of clear record. Following conviction, secured a non-custodial sentence on charges carrying a maximum penalty of life imprisonment.

HKSAR v Yang Hui-hong (FLCC 1203/2025)

•  Acted for the defendant on a charge of dealing with property known or believed to represent the proceeds of an indictable offence (money laundering), involving some HK$368,000 passing through a bank account said to be connected to an online investment scam. Following trial, the defendant was acquitted.