The royal decree to regulate digital asset-related transactions came into force on Sunday after it was published in the <i>Royal Gazette</i>.
Finance Minister Apisak Tantivorawong said in March that the law was necessary to comprehensively regulate cryptocurrencies and digital tokens to prevent money laundering, tax avoidance and crime.
The 100-section law defines cryptocurrency as digital assets and digital tokens.
It tasks the Security Exchange Commission (SEC) to control and regulate the digital assets.
All sellers are required to register with the SEC within 90 days of the law taking effect.
Sellers of digital tokens unauthorised by the SEC will be fined no more than twice the value of the digital transaction or at least 500,000 baht. They could also face a jail term of up to two years.
The decree was approved by the cabinet in March after going through the Council of State, which removed other assets from the law from the draft forwarded by the Finance Ministry, such as electronic data.
It was not meant to prohibit cryptocurrencies, initial coin offerings (ICOs) and other digital asset-related transactions, but to protect investors, he added.
The ministry and SEC will now work on organic laws requiring all digital asset transactions, including those of digital asset exchanges, brokers and dealers, to be registered with the relevant authorities according to the decree.