The £25m Rhyl High School, which opened on Wednesday, includes facilities for vocational courses such as a hair and beauty salon and a construction room.
It will also provide a base for 45 pupils from the nearby community special school, Ysgol Tir Morfa.
Work started on the new complex more than two years ago, built near the old school which will be demolished.
It has been funded by Denbighshire council and the Welsh Government.
The old school was described as dilapidated by the modernising education team in the council.
Head teacher Claire Armitstead said: "It is amazing. We have worked really hard for the last two years, even longer, probably five years, to try and make it happen. And it felt like it was always just a bit out of our reach.
"But today we've got children sitting in the building that we helped to create.
"I feel like we have done something right for the children of Rhyl and I think our children deserve this.
"We now have a building that is watertight, bright, light and I don't think you realise how important those things are to you until you haven't got it."

The California-based firm unveiled the five-seater car - its lowest-cost vehicle to date - on Thursday.
Mr Musk tweeted the total reflected the orders received by the end of Saturday.
Pre-orders of the Model 3 will not necessarily all translate into actual sales when the car is released, with first deliveries in late 2017.
It can be ordered in advance in dozens of countries, including the UK, Republic of Ireland, Brazil, India, China and New Zealand.
Potential car owners need to put down $1,000 deposits to reserve their vehicles.
Such has been the interest that Mr Musk tweeted the company was "definitely going to need to rethink production planning".
Mr Musk has said his goal is to produce about 500,000 vehicles a year once production is at full capacity.
The basic model will start at $35,000 (Â£24,423) and have a range of at least 215 miles (346km) per charge.
Tesla delivered 50,580 vehicles last year. Most of those were its Model S saloon, which overtook Nissan's Leaf to become the world's best selling pure-electric vehicle.
But the firm still posted a net loss of $889m (Â£620m) for 2015, partly because it spent $718m on research and development over the period.
It left Tesla with cash reserves of $1.2bn, down from $1.9bn a year earlier.
The company is facing competition from other electric cars with a similar price and range that will become available first, including General Motors' Chevy Bolt and BYD's Qin EV300.

Highlands and Islands Airports Limited (Hial) runs sites in the Highlands, Western Isles, Orkney and Shetland, Argyll and Dundee Airport.
Inverness was the company's busiest site with 657,661 passengers - 6% more than the previous year.
Sumburgh had an 8% increase in passenger numbers and Barra 14%.
However, Dundee's passenger numbers were down 17%.
Barra's runway is a strip of beach, which Hial said added to the appeal for tourists visiting the island.
Hial said because it was a publicly-funded company, it had historically operated at a commercial loss in order to sustain its lifeline services.
In 2014-15, the group recorded an operating loss of £442,000 compared to £3.8m on the previous year.
It said the improved performance was due to Scottish government subsidies returning to normal levels of £20.1m in 2014-15 from £14.9m in 2013-14.
A new secondary school in Denbighshire has officially welcomed the first of its 1,200 pupils.
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Tesla founder and chief executive Elon Musk says pre-orders of the firm's much-anticipated Model 3 electric car currently total 276,000.
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The operator of Scotland's 11 regional airports handled more than 1.4 million passengers in the 12 months to March 2015, according to its annual report.