This document reports on the 2nd release of the Underwater Services and the software underlying each service. This NEANIAS report, deliverable D2.6, comes out after the second thematic Underwater Services release, deliverable D2.5. Due to a delay in the delivery of U1 [UW_BAT] “Bathymetry mapping from acoustic data service implementation” this report has not been published end of October 2021 but in April 2022. The U1 service provides an advanced user-friendly, cloud-based version of the popular MB-System software, allowing processing bathymetric data through Jupyter Notebooks. The U2 [UW_MOS] service “Seafloor Mosaicking from Optical Data” delivers 2D/3D mosaics produced by a set of images and navigational data. The expected output is achieved by a processing pipeline based on in-house solutions and open-source libraries. Finally, the U3 [UW_MAP] service “Seabed Classification from Multispectral, Multibeam Data” provides an easy-to-use, cloud-based solution incorporating machine learning frameworks in order to identify different seabed classes. For each released service a point-of-access is provided, as well as the relevant documentation, which is organized under the NEANIAS documentation service at https://docs.neanias.eu/en/latest. This second services milestone sees the Underwater services integrated to NEANIAS several core services, which are an essential contribute to the TRL 7 level reached. The core services integrated are the Logging and Accounting services, the AAI service and the Data Sharing service. The U2 and U3 services are also using the Common UI (User Interface) service.1 In this deliverable, we describe, in detail, the progress and changes/enhancements made since the first release for each of the Underwater services.