There are various options from learned societies and open access publishers to commercial publishers. Some things to consider:
If you are not using a conventional publisher and need an ISBN for your publication the library can supply one. This might happen for example if you are publishing conference proceedings or a report.
An ISBN will be nationally registered and details available to booksellers. It is a unique product number which identifies your publication.
When your publication is ready for the ISBN simply complete the application form below. Send the completed form to LibraryResearchSupport@swansea.ac.uk. You will receive an ISBN number and we will register your publication in the national ISBN database. The cost will be met by the library.
You remain responsible for distribution of your publication and for dealing with legal deposit http://www.bl.uk/aboutus/legaldeposit/. Note that there is a legal requirement to deposit any publication published in the UK with the legal deposit libraries whether it has an ISBN or not.