Days at sea are the perfect opportunity to relax, unwind, and catch up with what you've been meaning to do. So whether that is going to the gym, visiting the spa, whale-watching, catching up on your reading, or simply topping up your tan, these blue sea days are the perfect balance to busy days spent exploring shoreside.

In comparison to Kailua-Kona, Hilo is often described as "the old Hawaii." With significantly fewer visitors than residents, more historic buildings, and a much stronger identity as a long-established community, this quaint, traditional town does seem more authentic. It stretches from the banks of the Wailuku River to Hilo Bay, where a few hotels line stately Banyan Drive. The characteristic old buildings that make up Hilo's downtown have been spruced up as part of a revitalization effort. Nearby, the 30-acre Liliuokalani Gardens, a formal Japanese garden with arched bridges and waterways, was created in the early 1900s to honor the area's Japanese sugar-plantation laborers. It also became a safety zone after a devastating tsunami swept away businesses and homes on May 22, 1960, killing 60 people. With a population of almost 50,000 in the entire district, Hilo is the fourth-largest city in the state and home to the University of Hawaii at Hilo. Although it is the center of government and commerce for the island, Hilo is clearly a residential town. Mansions with yards of lush tropical foliage share streets with older, single-walled plantation-era houses with rusty corrugated roofs. It's a friendly community, populated primarily by descendants of the contract laborers—Japanese, Chinese, Filipino, Puerto Rican, and Portuguese—brought in to work the sugarcane fields during the 1800s.One of the main reasons visitors have tended to steer clear of the east side of the island is its weather. With an average rainfall of 130 inches per year, it's easy to see why Hilo's yards are so green and its buildings so weatherworn. Outside of town, the Hilo District has rain forests and waterfalls, a terrain unlike the hot and dry white-sand beaches of the Kohala Coast. But when the sun does shine—usually part of nearly every day—the town sparkles, and, during winter, the snow glistens on Mauna Kea, 25 miles in the distance. Best of all is when the mists fall and the sun shines at the same time, leaving behind the colorful arches that earn Hilo its nickname: the City of Rainbows. The Merrie Monarch Hula Festival takes place in Hilo every year during the second week of April, and dancers and admirers flock to the city from all over the world. If you're planning a stay in Hilo during this time, be sure to book your room well in advance.

Included Shore Excursions:

• Best of Hilo and Akaka Falls
• Hawaii Volcanoes National Park and Pana’ewa Rainforest Zoo
• Land Of Frozen Fire

Acquaint yourself with Kahului, on a heavenly Hawaiian island that literally brushes against the sky. Kahului is lush Maui's principal town, enjoying an envied setting of immense natural beauty, cradled between the Valley Isle's twin volcanoes. It's the perfect location for a profound adventure among the island's cloud-wisped mountains, bamboo-framed hiking trails, and thrashing waterfalls. Kahului is a laid-back town and an important transport hub for Hawaii. Its sugar mill museum tells of plantation history, while juicy market stalls bulge below hauls of plump pineapples. Photogenic wild beaches like Kanaha Beach Park unravel along Kahului's coastline, offering turquoise waters glistening with Hawaiian beauty - perfect for kicking back and watching frothing waves unroll. More beaches unspool close by and are home to massive sea turtles who lumber towards the water as the sun climbs into the sky. Or find sandy curves of rusty red and deep black powder, formed by Maui island's sacred volcanoes. The colossal Haleakala shield volcano's crater is famous for otherworldly panoramas of rainbow-streaked terrain and towering cinder cones. Reach its heights to breathe in the crispest air imaginable, and drink in views of bubbling pink and fuchsia sunrises, or the inky-black sky illuminated with galaxies at night. Lush Puʻu Kukui, to the west of the island, is one of the wettest spots on earth, nurturing a densely vibrant land of waterfalls, steep valleys, and towering rock formations.

Included Shore Excursions:

• Maui Ocean Center & Sphere
• Iao Valley and Maui Tropical Plantation

The Kona coast, on Hawaii’s western shore, divides into two distinct areas – the north with spectacular sandy beaches followed farther up by a long bleak slope of barren lava trails from dormant Mauna Kea all the way down to the sea. Southwards, the hillsides are more fertile and there is still a feel of the old Hawaii. The Big Island’s main resort is officially called Kailua, but mostly everyone simply refers to it as Kona, or Kailua-Kona. It is by far the island’s most developed area. Whilst the main road, Ali’i Drive, is lined with shops, hotels and condominiums, most of the shoreline vista remains intact thanks to low-rise buildings. To show just how fertile lava can be when tended, miles of multi-hued bougainvillea and poinsettias line Ali’i Drive like a colourful lei. East of town is the 8,271-foot (2,521-metre) Mount Hualalai, where local people still earn a living growing vegetables and taro on small farms spreading over the side of the mountain. In the center of Kona stands the Hulihee Palace built as the governor’s residence in 1838. The relatively simple dwelling was heavily damaged during the last big storm and is now under restoration. The north end of downtown is home to Ahuena Heiau, where King Kamehameha spent the last years of his life. A dozen miles south of Kona at Kealakekua Bay is the site where Captain Cook was killed on his second voyage to Hawaii. South Kona is also the prime source of the famous Kona coffee.

Included Shore Excursions:

• Kona Highlights

Here is Hawaii's only true metropolis, its seat of government, center of commerce and shipping, entertainment and recreation mecca, a historic site, and an evolving urban area—conflicting roles that engender endless debate and controversy. For the visitor, Honolulu is an everyman's delight: hipsters and scholars, sightseers and foodies, nature lovers and culture vultures all can find their bliss. Once there was the broad bay of Mamala and the narrow inlet of Kou, fronting a dusty plain occupied by a few thatched houses and the great Pakaka heiau (shrine). Nosing into the narrow passage in the early 1790s, British sea captain William Brown named the port Fair Haven. Later, Hawaiians would call it Honolulu, or "sheltered bay." As shipping traffic increased, the settlement grew into a Western-style town of streets and buildings, tightly clustered around the single freshwater source, Nuuanu Stream. Not until piped water became available in the early 1900s did Honolulu spread across the greening plain. Long before that, however, Honolulu gained importance when King Kamehameha I reluctantly abandoned his home on the Big Island to build a chiefly compound near the harbor in 1804 to better protect Hawaiian interests from the Western incursion. Two hundred years later, the entire island is, in a sense, Honolulu—the City and County of Honolulu. The city has no official boundaries, extending across the flatlands from Pearl Harbor to Waikiki and high into the hills behind. The main areas (Waikiki, Pearl Harbor, Downtown, Chinatown) have the lion's share of the sights, but greater Honolulu also has a lot to offer. One reason to venture farther afield is the chance to glimpse Honolulu's residential neighborhoods. Species of classic Hawaii homes include the tiny green-and-white plantation-era house with its corrugated tin roof, two windows flanking a central door and small porch; the breezy bungalow with its swooping Thai-style roofline and two wings flanking screened French doors through which breezes blow into the living room. Note the tangled "Grandma-style" gardens and many ohana houses—small homes in the backyard of a larger home or built as apartments perched over the garage, allowing extended families to live together. Carports, which rarely house cars, are the island's version of rec rooms, where parties are held and neighbors sit to "talk story." Sometimes you see gallon jars on the flat roofs of garages or carports: these are pickled lemons fermenting in the sun. Also in the neighborhoods, you find the folksy restaurants and takeout spots favored by the islanders.