HMS Brocklesby is proud to be affiliated with the following organisations:
- Brocklesby Hunt: HMS Brocklesby has enjoyed a long affiliation with Brocklesby Hunt. The Hunt was formed in about 1700 and has been hunted continuously by the Earls of Yarborough throughout its history. The country as now constituted has existed since 1714, when Messrs. Vyner, Tyrwhitt and Pelham hunted it conjointly. At a later date the former two gentlemen retired, and Mr Pelham and his family continued to hunt the country. The Hunt territory now extends throughout Lincolnshire from the Humber Estuary to Market Rasen. The terrain is mainly arable, with some grass and very attractive woodland, particularly on Brocklesby Estate.
- Sea Cadets from the TS Falcon (Wisbech), TS Prince Charles (Mansfield), TS Wrangler (Lincoln) Units.
- West Lindsey District Council in Gainsborough, Lincolnshire.