Top Picks: Lanikai Pillbox Trail (Military Remnants, Ridge Trail, Windward)
Definitely one of the cooler hikes I have taken and my first ridge trail, I would highly recommend checking this spot out. It is relatively easy and short (less than a mile to the first pillbox) with truly amazing views. Finding the trailhead can be a bit confusing if you’re not sure where to look. It is in a residential neighborhood across the street from Mid-Pacific Country Club (a good GPS address: 266 Kaelepulu Dr, Kailua, HI 96734). Make sure you are aware of the parking rules; you may have to park down the block or on another side street, just read the signs. The trail head is not visible from the road, but you will see a little street (which looks like a driveway really) across from the golf course with an interesting tribal looking character and the house numbers: 269, 271, 275. Walk up this short drive and you will see the trailhead and you’re on your way. The trail is sort of make your own at the beginning, all spots lead to the same place you just have to pick what’s easiest for you. It’s initially pretty steep, but surprisingly not slippery (that may be very different after a rainfall). 
Keep heading up intuitively and you will reach your first ‘pillbox’ or abandoned WWII military bunker. 
You can try to get on top of it or go inside and check out all the graffiti, or just stand beside it. 
The views are panoramic and mesmerizing from the rigid mountains, to the golf course, neighborhood, and Mokulua Islands in the ocean. 
Soak it in. Some decide to head back after this short escapade, others continue on the narrowing ridge trail to the second pillbox. It’s a little unnerving at the start walking in the middle of two steep drop offs, but if you don’t have any real serious fear of heights you get used to it. 
The day we went happened to be extremely windy (not surprising for the windward side) which also added to the intensity. As the mileage went on I stopped being so cautious about my footing and just rolled with it naturally. There are times where the flora gets thick around you and we heard birds and saw a butterfly. 
The second pillbox was also great and not too different from the first. Continuously beautiful views! You can either continue on and walk through the neighborhood to loop your hike, or just head back the way you came.