I'm aware that Nepal is landlocked and does not posses a beach. In fact many people I met on my travels have never seen the sea, ever. But Pokhra (not to be confused with Pokhran in India, the site for our nuclear tests), which is a 40 minute flight or a 5-8 hour bus ride from Kathmandu evokes the same ethos that Goa does in India. It's the getaway, the sun and lake water, the firangs and trippers. It's most importantly the easiest gateway into the mighty Himalayas, in this case the Annapurna range. Again, due to my brilliant timing I could see no mountains but on most Oct/Nov and Feb/Mar days you can see the whole Annapurna Range distantly towering over the town of Pokhra. Like Goa, you can rent bikes and bicycles and like Goa, you can chose from a range of accommodation that can either dent or caress your wallet. There's also the never ending line of shops, bars and live music to keep you occupied.
If you like me is more of a romantic, deserted South Goa type, you should head to Begnas lake, 23 kms away (scroll down for photos). Or trek up one of the many hills surrounding Pokhra to get unparalleled green views.
Lord Shiva Cave temple a couple of Kms away. You can cross the lake, walk up to the Buddhist Stupa on the other side catching fabulous views on the way. In the photo below you would see a snow mountain range where you see clouds. From the stupa you could go around to see the Shiva Temple and then get back to the lake the long way around. Around 10 Kms totally.