Accommodation saturation is transcendental in island destinations; especially when we include it in the sustainability paradigm. A coastal tourism area is considered saturated when tourists feel the area is overbuilt. This can lead to unpleasant experiences that decrease tourist satisfaction—diminishing the competitiveness of the destination. This issue is especially relevant in insular areas. However, estimating optimal levels of accommodation density is complex, with many conceptual, methodological and operational controversies. Moreover, there is a lack of measurement data and assessment standards at the micro-local scale. The main objective of this paper is to analyse tourist accommodation density because it is commonly used to measure the level of saturation in urban coastal tourism areas. The intention is to identify from the perspective of overtourism, the weaknesses of using tourist accommodation density as a parameter to assess the urban saturation of coastal tourism areas located in the destination, the Canary Islands, Spain. A systematic method of observation and interpretation is employed to examine the use of density indicators and assess their efficiency. The main conclusion is to determine the optimal accommodation density. In order to achieve this, we must consider more than just the pressure and condition indicators; we also have to examine other related responses to the behaviour of the demand and, more specifically, the level of satisfaction of the tourists. The objective of this work is to evaluate the weaknesses of using tourist bed places as an indicator of the level of saturation in a coastal tourism area.