In tourism and travel, as in many other business sectors, big data is responsible for accurate decision-making. Typically, they are involved in customer demand forecasting, service personalization, as well as travel marketing, and pricing strategies optimization. From a European point of view, EU members of the travel & tourism industry are able to get a more realistic overview thanks to Big Data because it increases the sample base and does not rely on stated queries or intentions. What are the best practices to use them?