The ISSN Register provides authoritative information about serials and other continuing resources worldwide, thanks to the input provided by the 89 National Centres belonging to the ISSN Network. The ISSN Register, maintained by the ISSN International Centre, stores metadata, e.g. resource identifiers and links between resources, whose key role has been emphasized by the emergence of linked data. Access to ISSN Register information is provided by the ISSN Portal. The former portal was designed in 2004 and its search options did not allow users to discover and reuse data easily. Moreover, information was only available to ISSN customers. Since October 2016 the ISSN International Centre has been working on the implementation of a new portal, which started operating in January 2018. This new portal gives access to a sub-part of the data elements of the ISSN Register as linked open data. It also offers enriched and linked information to its subscribers, who benefit from enhanced services like the automation of data ingestion. Features such as data search and display and retrieval have also been greatly improved. Via interactions with other data repositories, the ISSN Register reuses additional information to foster information discoverability in the new ISSN Portal.