The attack took place two months ago at the end of the summer. Stockholm District Court heard that the woman had been sitting crying when two of the teenage boys came and offered her a beer and comforted her.
She said she had declined the alcohol but ended up sitting with the teenagers at a nearby viewpoint looking over the city. At first the atmosphere was calm and she even phoned a friend. But then one of the men gripped her neck, ripped her clothes off and raped her.
The woman said that several other boys then arrived and she was raped a further five times, by at least four different people.
She managed to escape from the group at around 3am and board a night bus in the area, she explained.
On Thursday the court sentenced two of the boys, who are all aged between 15 and 18 years old, to six months in a juvenile detention centre and another to nine months. A third boy who was previously arrested was not brought to trial, Swedish tabloid Aftonbladet reported.
All of the teenagers are from north Africa and had been living in a tent camp in Stockholm.
After the verdict, the woman told Aftonbladet she thought it was “sick” that the young men had been given such short sentences but said she was “glad that they were all convicted”.
While her physical wounds have healed, she said: “mentally I feel bloody awful”.
Södermalm is one of Stockholm's major islands, situated south of the city's Old Town. Previously an industrial area with a reputation for violence, it has transformed into a trendy neighbourhood in recent years, popular with both locals and tourists.