The Kohala Coast on the west side sees two to three times more whales than anywhere else on the island, but Kona and Hilo are solid too.
Kohala Coast
Puʻukoholā Heiau National Historic Site — its name means 'Hill of the Whale,' and this restored temple built by Kamehameha I offers panoramic ocean views over Kawaihae Harbor, plus exhibits and parking (it gets hot and windy). Lapakahi State Historical Park, a 600-year-old fishing village just north, has elevated views and fewer crowds — bring water and sun cover. Kapaʻa Beach Park near Pololū is a mellow picnic-and-watch stop; grab a pizza from K.O. Pizza or a sandwich from Kohala Grown Market in Hāwī on the way. And Hapuna Beach — one of the island's best — lets you scan the horizon between swims; stay at the Westin Hapuna for direct access.
Kona Coast
Any sandy-bottom bay between Kailua-Kona and Keauhou offers shore spotting in humpback season, and Kona's flat, calm water makes spouts easy to see. The Four Seasons Resort Hualālai sits above waters where humpbacks pass just 300 yards offshore.
East Side (Hilo)
Hilo Bay has several vantage points to watch whales cruise past the breakwall, with parking and shade at the northern point (no facilities). Just north of town, the Hawaiʻi Magic Skies B&B Farmstay offers elevated second-floor views, binoculars and chairs — a peaceful farm perch. Whales are less frequent on this side than the west.