East Oahu, Lanikai area
The unique light blue mixed with emerald green sea color on the east side of Oahu adds a lot of character to the Pillbox hiking trail. The first 10 minutes of the hike are relatively steep, so you may need to hold onto the tree trunks beside you and walk slowly. Except for rainy days when it can be slippery, it is generally not too difficult. After the first 10 minutes, you will reach the halfway point, where you can already see the very beautiful Lanikai Beach and the two small islands, the Mokes.
Southeastern corner of Oahu, Hawaii Kai area
This hiking trail is a very local attraction. It's basically only frequented by locals. Although it takes about 4 hours, the path is mostly flat. Along the way, you'll pass through forests with different types of trees. About halfway up, you can see a distant view of Hawaii Kai. In the last 20 minutes, there is a section with stairs. From there, the scenery becomes very spectacular. Once you reach the top, it's even more surprising! The view stretches from Diamond Head in the south to Rabbit Island in the east, encompassing a quarter of Oahu's land.
Central Oahu, Aiea Area
Aiea Loop is a very leisurely hiking trail. Officially, it takes 3 hours. The entire trail is relatively flat forest paths with hardly any places that require heavy breathing. However, if it rains, some sections can become slippery and muddy. Since the entire trail is within the forest, it stays quite cool. This trail is suitable for those who feel a bit lazy but still want some outdoor time. The entire hiking trail features many peculiar trees, inverted tree roots, giant tree branches hanging in mid-air, and naturally formed tree circles.
West Oahu, Ka'ena Region
This is also a very, very easy hiking trail, almost like a walk. However, it is a very worthwhile spot for photography. Located at the westernmost part of the island, it is an old coastal road from many years ago. Due to being closed off for a long time, it is now essentially a very rugged stone and dirt road. But because the entire route runs along the coast, there are many spots where you can take beautiful photos of the coastline and coastal rocks. Additionally, it is a place where sea lions in the area take their afternoon naps.
East Oahu, Makapu'u Area
Special note: This tidepool is accessed via the Makapu'u lighthouse hiking trail. The difficulty level does not include the initial lighthouse trail segment. Starting from the tidepool entrance, there is no defined path; you need to find your own way down the rocks. There are also many small stones, so it is recommended to climb slowly. Otherwise, slipping on small stones and rolling down the hill can be quite serious.