Significant advancements in deepwater subsea boosting technology, operations, and surveillance are represented by two Shell world-class developments: Perdido in the Gulf of Mexico (that will begin production in 2010) and BC-10 offshore Brazil (on stream since July 2009). These novel projects continue the long tradition of Shell's leadership in the challenging deepwater environment by development and application of a novel seafloor boosting system. The subsea boosting system utilized by both the Perdido and BC-10 assets for increased ultimate recovery and higher production rates is based on the application of electric submersible pumps (ESP) located in a shallow seafloor caisson. These caissons collect production fluids from the manifolded subsea wells and prevent significant loss of ESP performance due to excessive gas production by passive liquid/gas separation.Extensive testing and qualification of the subsea boosting system was undertaken prior to final configuration selection including construction of the world's only 1500-hp ESP test facility capable of controlling multi-phase fluid viscosities and temperatures. A comprehensive suite of tests was performed in conjunction with Baker Hughes Centrilift replicating the expected conditions and performance requirements for both deepwater assets. This paper describes the subsea boosting system maturity process, and discusses the current status of each development and related key learnings.