The 81-bedroom hotel, in Marine Parade, has been delivered by Roffey Homes as part of the redevelopment of the Beach Hotel.
Opening on December 14, visitors will soon be able to relax with stunning views of the sea and the downs from their bedroom windows.
Roffey managing director Ben Cheal said: “I feel very proud that the initial concept for the site has come to fruition and that we have been able to help provide the first (new-build) hotel in 100 years in Worthing.
“Hopefully, the economic and regenerative impacts to the town will be significant.”
The new hotel – which will rival other chain Travelodge, also on Worthing seafront – offers a range of rooms, including several with fully-accessible disabled facilities.
The best rooms have dual-fronted windows, allowing views of the seafront in two directions.
A dining room, facing the beach, will be open to the public for breakfast and supper.
Parking for 37 cars is accessible via Brunswick Road.
Premier Inn’s 25-year lease was signed after a lack of interest from luxury hotel companies, which was the original vision for the site.
Mr Cheal told councillors last year: “The hotel market has changed over the last 40 years and we have to be realistic about this.”
The new hotel was made possible as part of the wider Beach Residences development.
This provided around 50 apartments and penthouses featuring between two and four bedrooms.
Mr Cheal confirmed all the properties had now been sold, with one under reservation.
He said: “The hotel forms part of the wider development. The residential part enabled the hotel to be provided on this seafront location.”
Worthing and Adur Chamber of Commerce chief executive Tina Tilley said anything which brought business into the area was positive – but hoped it would attract a diferent market to those targeted by the established bed and breakfast and hotels in the town.
She said: “Premier Inns are very well known for businesspeople travelling and some companies use them as their preferred accommodation for employees.
“It may be of some concern for the bed and breakfasts but hopefully it will be appealing to different markets.
“We do want to have more accommodation for people to stay.”