The world isn’t flat and Hawaii tourism isn’t, either — especially from the domestic side.

Tourism in 2018 is expected to surpass 2017, which so far is shaping up to be the best tourism year on record, according to experts at the annual Global Tourism Summit, which kicked off Tuesday at the Hawai‘i Convention Center and is expected to attract some 1,689 attendees through Thursday.

“These past two years were projected to be flat,” but “travel demand has exceeded all expectations,” George D. Szigeti, Hawaii Tourism Authority president and CEO, said Tuesday at the conference opening.

“Hawaii’s tourism success in 2017 has been far greater than projected,” Szigeti said. “Our leading industry and provider of jobs is enjoying great success.”

The Department of Business, Economic Development and Tourism’s Aug. 11 forecast anticipates visitor spending will reach $16.8 billion this year, with 9.2 million visitors arriving, 290,000 more than last year. If Hawaii breaks 2016 records, this would be the sixth year in a row that state tourism has achieved visitor and spending growth.

While growth is coming from a variety of sources, expansion of the domestic market, which made up 67.5 percent of all arrivals in 2016, has been key to 2017’s success. July was the 14th straight month to show visitor arrival and spending gains. Through the first seven months of this year, arrivals climbed by nearly 5 percent to 5.5 million visitors, with the domestic market accounting for 3.6 million, or 67.7 percent.

Jay Talwar, chief marketing officer for Hawaii Tourism USA, said continuation of a marketing campaign that lets travelers tag #LetHawaiiHappen to share their personal Hawaii vacation memories through social media has highlighted authentic experiences on all six major Hawaiian Islands and yielded robust results.

“It’s working extremely well,” Talwar said, citing a bump of about 10 percent in those who say that they plan to visit Hawaii in the next 24 months among those who’ve seen the campaign.

Talwar said Hawaii Tourism USA also will continue its marketing blitzes, with the next mainland saturation campaign planned for October. The blitz will focus on highlighting cuisine, culture, authenticity and the state’s six island brands, he said.

Marketing will be increasingly focused on avid explorers, the 25- to 35-year-old crowd, and the mobile platforms that it takes to reach them, he said.

“We’ll focus on changing the perception of Hawaii from touristy and irrelevant to the place we all know and love … this incredible place that they just don’t know about yet,” he said.

Talwar said the domestic market is expected to play a big role in buoying 2018, too.

DBEDT anticipates that arrivals will grow to 9.4 million visitors in 2018, a 1.4 percent gain over 2017. Expenditures are expected to reach $17.1 billion next year, hitting a new tourism benchmark when it surpasses 2017 expenditures by 2.2 percent.

Talwar said several factors bode well for strength in Hawaii’s 2018 domestic tourism market, including solid GDP growth and low oil prices.

Additional airline seats in 2018 should also take the domestic market higher, he said.

Beyond 2018, DBEDT anticipates visitor arrivals will increase 1.5 percent in 2019 and 2020. Visitor expenditures are expected to increase 3.6 percent in those same years.