The paddle itself is on sometimes choppy waters, but waves are minimal. Be prepared for wind, as Kailua Beach is one of the premiere windsurfing spots on the Hawaiian isles. You can paddle to a very small bird sanctuary island about mile from the beach put-in, and the adventurous can paddle to the famed Mokolua Islandsan island pair that is seen in virtually every photo spread of Oahu. The Mokes, as they are called, are like two small peaks in the aqua blue waters of the Pacific, and are about 1 mile east of your put-in. Likely the biggest risk of your journey lies in the open water crossing to the Mokes, so plenty of sunscreen and water and a PFD are crucial. Sharks, although found throughout the island state, are not known for eating paddlers in this area of the island, which is reassuring if a rogue wave lifts an unskilled paddler off the SOT and into the drink.
Paddling back toward shore from the Mokes, due west, will bring you to Lanikai Beach, with its fancy Hawaiian homes (think the late Don tiny Bubbles Ho and other well-heeled Hollywood types) and white sand beach. On Oahu, all shorelines and beaches are public property, so you can land at any site that grabs your fancy, even if it feels like youre directly in someones back yard. A quick paddle mile around the bend brings you back to Kailua Beach, where you can re-dolly your kayak and walk it back to the outfitter. No high end performance kayaks are available at Kailua Beach, but the SOTs with heavy paddles can still be a riot.
Do not forget to enjoy the deli, and often outside grill, and Kalapawai Market, a nifty store that is right at the beach and is a fixture of the area for paddlers and surfers. Everything from t-shirts to coffee to wine is available at this rustic looking small and friendly store, right on the edge of the beach park and right by the kayak rentals.
I have traveled to Oahu generally at wintertime, and the other potential paddling spots (North Shore, Waimea) are far too violent to consider; although they may be paddling candidates for summer fun. Audrey Sunderlands Paddling Hawaii book is helpful. But Kailua Beach and Lanikai Beach are truly memorable experiences for paddling on Oahu.
Hang ten, enjoy.