This dataset contains records of plant-pollinator interactions, flower-visiting insect communities, floral resource abundance and richness, and experimental treatments from two Arctic grassland ecosystems in Kilpisjärvi, northern Finnish Lapland. Data were collected in 2022 from a long-term experimental setting established within the Nutrient Network (NutNet). The study included two grassland sites, a low-productivity tundra grassland and a high-productivity montane grassland exposed to factorial combinations of grazing exclusion and nutrient addition treatments. Experimental treatments consisted of unfenced control plots, nutrient addition (NPK), grazing exclusion (Fence), and combined nutrient addition with grazing exclusion (NPK + Fence). The dataset includes plot-level records of flower-visiting insects observed during standardized visitation surveys conducted during peak flowering time. Interaction data document insect family identity and visited plant species. Flower-visiting insects were identified to family level, and flowering plant species associated with each interaction were recorded. The data further include mean summaries of flower species abundance, richness, and Shannon diversity per block for the years 2020 and 2022, published in another article (doi: https://doi.org/10.1002/oik.11562). This flower data is derived from the original data which contain floral measurements based on standardized flower-unit counts per plot.  Metadata describing site characteristics is provided. The dataset supports analyses of how grazing exclusion and nutrient enrichment influence Arctic flower-visitor communities and plant-pollinator interaction structure.