Lembar is in West Lombok.
Visitors to Lembar are normally there because of the ferry to and from Bali. There's little reason to staying there.
The port of Lembar is 22km south of Mataram.
You can take a bemo from Mataram to Lembar Harbour. The fare should be about Rp 15,000, more if you are carrying a lot of luggage as it fills up the passenger carrying area, this is normal practice as the bemo's carry both people and goods including produce to the markets..
There are slow public ferries from Padang Bai (Bali) every hour. The trip normally takes four hours (but it can be considerably longer in poor weather) and costs Rp 44,000. This service runs 24 hours a day.
Arriving at Lembar Harbour do not let a porter take your bags unless you have negotiated absolutely what you will pay before he puts his hands on your bags. Best to avoid the service completely if possible as it can be fraught with complications over prices.
Getting from Lembar harbour
If you're arriving in Lembar and need transport, you'll find the Lembar bemo drivers hard bargainers.
If you are leaving from Lombok, chances are high that someone will approach you and offer the ticket to Bali for same or cheaper than going the current rate of Rp 44,000 (August 2015). They'll also try to move you past official ticket offices (at the entrance gates of the harbour). It may be cheaper, however, you won't get an official ticket, or get only second part of it (the first one normally goes to the security on the pier). So, you may end up without a valid ticket and, if some security check happens, may have to pay again and suffer a lot of confusion. Just buy the ticket at the official ticket booth.
Not a lot to see at Lembar other than the ferry docking area and the nearby sea port area. The surrounding countryside is quite attractive and the drive through to Mataram or the west coast is scenic and interesting with quite intensive agricultural pursuits lining the sides of the road.
This is really just a transit point, just try to get in and out as quickly as possible.
There are a few local warungs that cater to the port workers and transport drivers waiting to load their vehicles. Food and snack vendors also board the ships and make the crossing hoping to sell to the passengers during the voyage. A well prepared traveller may prefer to visit a supermarket or a trusted warung selling "nasi bungkus" or take away food and some drinks including bottled water before departing by road for Lembar. The seas can become rough so choose carefully.
Warungs near the dock area will have drinks available for sale but you may prefer to prepare yourself with some refreshments prior to departing to the dock. The ships do not provide clean drinking water so you will either need to bring your own drinks or purchase from vendors on the ferry. Alcohol is not sold on the ferry and the consumption of alcohol in public places is not condoned either in Lombok or Bali and that includes the sea in between.
There's little accommodation in Lembar and no advantage in staying.
The ferries used on the run between Lombok and Bali do not conform to many Internationally recognised safety and operational standards.
There is a small Police post just inside the main entrance gate to the port area and a larger Polda national police base nearby.
Mobile phone towers ensure you're never out of touch. Telekomsel's Simpati SIM card has a reasonably good signal in the Lembar area and for a short distance out to sea. XL Comm SIM cards also provide coverage in the area. Coverage can be unreliable and inconsistent.