How you choose to get here however depends very much upon how long you intend to stay, and how much energy you feel like exerting!
#1 Take the public bus
Morocco can be a little confusing, in that dependant upon which company bus you intend to take, they all leave from different parts of a city - Essaouira is no different.
For buses to Sidi Kaouki (run by 'Lima Buses'), you need to make your way to Bab Doukkala, a large square just outside the medina walls (see the map below). Once you get here, ignore everybody that attempts to 'help you', specifically if they're a taxi driver - they will try to tell you that the next bus isn't for two hours to get a fare. Instead, you need to look the stand that serves Lines 1 - 4. It has a very obvious sign, and clearly states that line 2 is heading to Sidi Kaouki.
Buses run regularly throughout the day, with departures at 07.20, 09.10, 11.30, 13.30, 16.00 and 18.30. These buses take around 30 minute, and costs 7dh. You will be handed a small ticket when you pay, make sure you keep this as it will be collected by someone else later.
Just one word of warning for the return journey: After being advised by our bus driver that there was a return journey at 5 p.m., we arrived at the bus stop a little early. At 4.50 p.m. however, a small beaten up minivan heading to Essouira stopped for us. We still don't know whether this was indeed the bus we were supposed to catch (we arrived on a proper bus) but to be extra careful, get to the stop a little early.
#2 jump on a bicycle
Upon deciding to visit Sidi Kaouki, we always intended to cycle there - it seemed like a great way to see a little more of the area and to get in some exercise. However, after calling in at a couple of bike rental places, we decided that the cost simply wasn't worth it.
Although we found one chap who was willing to rent a couple of rust buckets for 200dhs, the going rate for decent bikes was 150dhs each. We decided that that money could be better spent on fresh seafood!
If you do decide to rent one, expect the cycle to take around an hour, depending upon how fit you are and how hot it is. The road is flat (albeit a little boring in parts) and the cycle would be completely manageable in the cooler months. Please note that we would not recommend this in the height of summer!
#3 haggle for a taxi
Although it's never going to work out cheaper than the bus, if there's a few of you and you'd prefer to avoid public transport, feel free to take up one of the Bab Doukkala chaps on their offer. It might take some haggling, but you should be able to negotiate him down to 15dhs/seat or rent the entire vehicle for 100dhs.