A second coronavirus case has been confirmed at the Sipoonjoen koulu school in the southern municipality of Sipoo, according to local officials.
The pupil's infection was confirmed on Thursday, two days after another of the school's students was diagnosed with Covid-19, the illness caused by a coronavirus infection.
Following that development, 15 other students and a few teachers at the school were ordered into quarantine as a precautionary measure.
Around 20 students and staff members were quarantined after the first student's infection earlier in the week.
Meanwhile, other classes are set to continue on school premises. Sipoonjoen koulu serves around 330 students in grades 7-9.
Over the weekend it was reported that fourth, fifth and sixth graders at the Söderkulla skola - another Sipoo school - would need to resume remote learning from home because a significant portion of staff went into quarantine after coming into contact with an infected individual, according to the municipality which is located some 40 kilometres northeast of Helsinki.
Additionally, one teacher and 13 pupils at Sipoo's Gumbostrands skola elementary school were also placed in quarantine as a precaution earlier this week after a school staff member was confirmed to have a coronavirus infection.
Following months of distance learning, the government ordered the country's schools to be reopened on 14 May.
Edited at 2:45pm on 22.5 to add information about the quarantine situation at Gumbostrands skola.