The aim of this article is to investigate two external flexible forms of employment—the leasing of workers through Temporary Work Agencies (TWAs) and the contracted workers employed through Business Service Providers (contractors). Undoubtedly, these two forms of employment are complex and often give rise to confusion. First, this article reviews the characteristics of these types of workers and the operation of these businesses. Second, it presents the results of a mixed method of empirical research (quantitative and qualitative) regarding contracted workers. Our sample was 365 contracted workers from the cities of Athens, Thessaloniki and Patras, Greece. In particular, quantitative research is conducted using a methodology called RDS (Respondent Driven Sampling) that is innovative in the field of labour economics and labour relations. Some significant findings of our qualitative research are used to improve, extend, and interpret the quantitative results. Our research proves that contracted workers, who are employed at the premises of the banks, are leased workers, and the contracting undertakings usually operate unlawfully as TWAs. Our research proves that Banks in Greece are using “pseudo-contracting” to circumvent the European Directive 2008/104/EC and the Greek Laws 4052/2012 and 4254/2014, both of which provide institutional protection to workers leased through TWAs. In more detail, the relevant European Directive and the Greek Law 4052/2012 provide salary equality and equal labour rights for the leased workers in Greece and the EU, when they share the same qualifications as the permanent employees of the user undertakings. The employers’ aim in adopting this policy is mainly to pay lower salaries to contracted workers, who in practice have the characteristics of leased workers.