The practice of pumping and dumping cryptocurrencies entails artificially boosting their value through coordinated acts, which usually leads to unlawful conduct and market manipulation. The legality of pump and dump activities depends on the jurisdiction where they occur. Market manipulation is illegal in traditional financial markets, but that is not always the case with cryptocurrencies. Regulators and law enforcement are increasingly focusing on illicit conduct in the crypto industry. It is best to seek legal professionals or regulatory authorities for up-to-date information on the legality of pumps and dumps in your specific country.