Physical proximity access to amenities and innovative and liveable environments found in metropolitan centres have been highlighted as factors that encourage the clustering of knowledge workers (KWs), that is, workers in knowledge-based industries. This paper studies how proximity to metropolitan cores encourages spatial clustering of KWs and affects their commuting patterns. To do this, we analyse the clustering and commuting patterns of KWs in the Barcelona (BMA) and Helsinki (HMA) metropolitan areas and measure their levels of concentration and polycentrism. Results show that metropolitan core in both metropolitan areas retains a large amount of commuting although the physical proximity to the metropolitan core becomes a key factor for spatial clustering of KWs only in the Barcelona case. In Helsinki, spatial clustering of KWs mainly follows suburban spatial patterns; in that sense, long commutes to the metropolitan core do happen.