National Lottery players are being offered two-for-one entry to Arundel Wetland Centre.
The deal is available from Monday, December 11, to Friday, December 15, as a thank you for the £10million-plus WWT has received from the Heritage Lottery Fund over the past 20 years.
Full-paying adults just need to present a National Lottery ticket or scratchcard to take another person into any WWT centre, including Arundel, for free.
Visitors can get close to fascinating animals, learn about amazing habitats and enjoy unique winter wildlife spectacles.
Hannah Clifford, from WWT, said: “We’re so pleased to be able to say a big thank you to National Lottery players who have helped us ensure that healthy wetland nature thrives and enriches lives here and around the world.
“We’re really looking forward to welcoming them to our centres and hope they’ll enjoy exploring our beautiful reserves and meeting our amazing wildlife up close.
“Winter is a great time to visit as nature provides some spectacular sights from kingfishers to roosting marsh harriers.”
The support from National Lottery players has contributed hugely to enabling WWT to continue its charity work to conserve, restore and create wetlands, save wetland wildlife, and inspire everyone to value the amazing things healthy wetlands achieve for people and nature.
Lottery-funded projects have helped WWT create new wetland habitat, build accessible new hides, run education projects and open new visitor centres.
The admission offer is part of a wider scheme for National Lottery funded visitor attractions across the UK.
Ros Kerslake, chief executive of the Heritage Lottery Fund, said: “December is a wonderful time to experience the UK’s rich, diverse and exciting heritage, which has been transformed by more than £7bn National Lottery funding since 1994.
“This is a small gesture of thanks and a way of giving something back to the people who buy tickets.”