This study identifies iceberg indicators for welfare assessment in sows and piglets to enhance feasibility and sustainability of available protocols. Indicators of the Welfare Quality(R) protocol and of a German protocol were collected over 65 farm visits to 13 farms in Germany between September 2016 and April 2018. Data were analysed using partial least square structural equation modelling (PLS-SEM). A hierarchical component model was built (animal welfare = higher-order, Welfare Quality(R) principles = lower-order components). In sows, welfare was revealed to be most influenced by the principles good housing, good health and appropriate behaviour (path coefficients = 0.77, 0.86, 0.91). High coefficients of determination R-2 indicated a large amount of explained variance (good housing R-2 = 0.59, good health R-2 = 0.75, appropriate behaviour R-2 = 0.83). Stereotypies was the indicator most valuable to assess sow welfare. Additionally, the final model included the indicators panting, shoulder sores, metritis, mortality and an indicator assessing stereotypies in resting animals (indicator reliabilities 0.54-0.88). However, the model did not include the indicators lameness and body condition, which may be due to the farm sample. Welfare of piglets was most explained by the indicators carpal joint lesions, mortality, sneezing and undersized animals (indicator reliabilities 0.48-0.86).