Penelitian ini bertujuan mengetahui learning loss pada pelajaran biologi di masa pandemi Covid-19 yang ditinjau dari pelaksanaan praktikum biologi di SMAN 2 Tarakan. Metode penulisan dalam penelitian ini adalah deskriptif kualitatif. Pengambilan data pada penelitian ini menggunakan kuisioner, wawancara, observasi, dan studi dokumenter. Subjek pada penelitian ini adalah siswa kelas XI MIPA, kepala sekolah dan guru mata pelajaran biologi. Hasil penelitian menunjukkan bahwa kegiatan praktikum biologi di masa pandemi Covid-19 dapat terlaksana tergantung situasi berdasarkan ketersediaan alat dan bahan praktikum serta kesiapan siswa, sehingga persentase keterlaksanaan praktikum biologi menurun selama pandemi Covid-19 dari persentase 57,14% (cukup baik) menjadi 13,33% (sangat kurang baik). Terjadi learning loss pada pelajaran biologi di masa pandemi Covid-19 ditandai dengan menurunnya keterampilan akademis pada mata pelajaran yang berpraktikum, menurunnya keterampilan dan pengetahuan terkait mata pelajaran yang berpraktikum, terhambatnya kemajuan atau pertumbuhan akademis siswa, menurunnya pengetahuan faktual dan prosedural siswa, kemunduran akademik dan kerugian pada jenjang pendidikan. Pembelajaran daring tidak sepenuhnya memberikan pengembangan keterampilan kerja ilmiah siswa.

The research aimed to figure out the biology learning loss during the Covid-19 pandemic viewed from the implementation of biology practicum at SMAN 2 Tarakan. This study was classified into descriptive-qualitative research. The data were collected through questionnaires, interviews, observations, and documentary studies. The research subjects were Grade XI Science Students, school principals, and biology teachers of SMAN 2 Tarakan. The results showed that biology practicum activities during the Covid-19 pandemic could be performed depending on the situation based on the availability of practicum tools and materials as well as the students’ readiness. Thus, the percentage of biology practicum implementation decreased during the Covid-19 pandemic from 57,14% (good enough) to 13,33% (very poor). The biology learning loss the Covid-19 pandemic was marked by the decreasing academic skills and knowledge related to practicum activities in certain subjects, delayed academic progress of growth, decreasing factual and procedural knowledge, as well as academic setback and loss at education level. Online learning did not fully develop the students’ scientific skills.