The 31-year old Russian identified as Andrew Ayer was arrested while he was at a cafe on Sunset Road, Setiawan said.
The police searched him and found six packets of hashish inside his backpack, he said.
The search was also conducted at his homestay but no evidence was found, he added.
The Russian admitted to selling the hashish after the buyer first transferred money into his bank account. He later waited for the buyer at the address they agreed upon.
"After taking the hashish the suspect waited for the subscribers in Dewi Sri, Kuta and Badung areas," he said.
Ayer has been staying in Bali since January 2019 using a vacation visa, Setiawan said.
He only sold the hashish to foreign tourists for Rp2.5 per gram, he said.
The Russian national has been charged with violating Article 111 paragraph (1) of the narcotics law that carries a maximum sentence of 12 years and a maximum fine of Rp8 billion, and Article 114 paragraph (1) of the narcotics law with a maximum sentence of 20 years and a maximum fine of Rp10 billion.