A dataset of 227 oligochaetes and 373 chironomids occurrence records from the subalpine Lake Maggiore, a large and deep temperate lake in Northern-Western Italy and Switzerland was developed within the Interreg Italy-Switzerland 2014-2020 Parchi Verbano Ticino Project (ID:481668) funded by the European Regional Development Fund (ERDF). The lake belongs to the national (LTER-Italy), European (LTER-Europe) and International (ILTER) long-term ecological research networks. Data were collected during the summer-autumn period in 2019-2021. Chironomids (Insecta, Diptera) and oligochaetes (Annelida, Clitellata) were identified to genus/species gr./species level by the authors. All 600 occurrence records are georeferenced and organised in a standardised Darwin Core Archive format. These data gathered along the littoral areas of Lake Maggiore will contribute to the development of common implementation strategies for shared and sustainable water management level of the lake, with particular reference to the protected natural areas (sites belonging to Natura 2000 network in Italy and to the Emerald Network in Switzerland). The authors strongly believe in the great potential of open access occurrence records in biogeographical studies and ecological research in the context of global environmental changes. For that reason, the dataset has been uploaded to the Global Biodiversity Information Facility (GBIF), an intergovernmental free and open access biodiversity data infrastructure.