This dataset provides quality-controlled stream temperature time series from 3 freshwater monitoring sites on the West coast of Vancouver Island, within the Mowachaht-Muchalaht First Nations territories. The three sensors were installed on May 29, 2024 and removed on May 28, 2025, producing a dataset of about 1 year. Temperature data were collected using in-situ sensors and processed to produce one representative time series per site at a uniform 10-minute resolution. Data processing included consolidation of raw sensor files, verification of timestamps and sampling intervals, and application of standardized quality flags informed by automated checks and field documentation. Where sensors were replaced at the same location, records were merged to maintain continuity, and periods affected by site changes or known influences were retained and identified through flags. All timestamps are reported in a fixed local time zone to ensure temporal consistency.