<p>I understand when I create one, I can define it to be single zone, multi zonal or regional and understand these can’t be changed after creation but would be good to know what type an existing cluster is.
Is there anyway I to tell the type of cluster from the dashboard or using the gcloud sdk?</p>

Rubans
<p>On GKE you can crate <a href="https://cloud.google.com/kubernetes-engine/docs/concepts/types-of-clusters" rel="nofollow noreferrer">3 types of clusters</a> based on location.</p>
<p><a href="https://cloud.google.com/kubernetes-engine/docs/how-to/creating-a-cluster" rel="nofollow noreferrer">Single-zone clusters</a></p>
<blockquote>
<p>A single-zone cluster has a single control plane (master) running in one zone. This control plane manages workloads on nodes running in the same zone.</p>
</blockquote>
<p><a href="https://cloud.google.com/kubernetes-engine/docs/how-to/creating-a-multi-zonal-cluster" rel="nofollow noreferrer">Multi-zonal clusters</a></p>
<blockquote>
<p>A multi-zonal cluster has a single replica of the control plane running in a single zone, and has nodes running in multiple zones. During an upgrade of the cluster or an outage of the zone where the control plane runs, workloads still run. However, the cluster, its nodes, and its workloads cannot be configured until the control plane is available. Multi-zonal clusters balance availability and cost for consistent workloads. If you want to maintain availability and the number of your nodes and node pools are changing frequently, consider using a regional cluster.</p>
</blockquote>
<p><a href="https://cloud.google.com/kubernetes-engine/docs/how-to/creating-a-regional-cluster" rel="nofollow noreferrer">Regional clusters</a></p>
<blockquote>
<p>A regional cluster has multiple replicas of the control plane, running in multiple zones within a given region. Nodes also run in each zone where a replica of the control plane runs. Because a regional cluster replicates the control plane and nodes, it consumes more Compute Engine resources than a similar single-zone or multi-zonal cluster.</p>
</blockquote>
<p>Easiest way is to check in your GKE dashboard, <code>location</code> of Cluster.
<a href="https://i.stack.imgur.com/jBsGi.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/jBsGi.png" alt="enter image description here" /></a></p>
<p><code>Zonal Clusters</code> have specified only one <code>zone</code> which in my case is <code>us-central1-c</code>.</p>
<p><code>Regional Clusters</code> have specified <code>Region</code> which may contains many zones. In my case location is <code>us-east1</code> without any <code>-X</code>.</p>
<p>When you are creating <code>Regional Cluster</code> you can also specify which <code>zones</code> should be added as default.</p>
<p><a href="https://i.stack.imgur.com/P4C2p.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/P4C2p.png" alt="enter image description here" /></a></p>
<p>Also if you will go to your cluster details you can see different options.</p>
<p><code>Zone Cluster</code>:</p>
<p><a href="https://i.stack.imgur.com/02Hiy.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/02Hiy.png" alt="enter image description here" /></a></p>
<p>In <code>zonal cluster</code> your <code>Master zone</code> and <code>default zone</code> are the same.</p>
<p><code>Regional Cluster</code>:</p>
<p><a href="https://i.stack.imgur.com/y7Xrk.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/y7Xrk.png" alt="enter image description here" /></a></p>
<p>In <code>regional cluster</code> you have specified <code>region</code> and <code>default zones</code> which can be chose during cluster creation.</p>
<p>In short. On GKE Cluster Dashboard in your location if you have <code>Region-Zone</code> (us-central1-c, where <code>us-central1</code> is <code>region</code> and <code>-c</code> is <code>zone</code>) its zonal.
If you have only <code>Region</code> like <code>us-east1</code> its <code>Regional cluster</code>.</p>
<p><strong>If you would like use gcloud CLI</strong></p>
<p>You can use <code>gcloud container clusters list</code> and check if <code>location</code> have specified <code>zone</code> like <code>region-a</code>, <code>region-b</code>, <code>region-c</code>.</p>
<pre><code>$ gcloud container clusters list
NAME       LOCATION       MASTER_VERSION  MASTER_IP     MACHINE_TYPE   NODE_VERSION    NUM_NODES  STATUS
zonal-1    us-central1-c  1.14.10-gke.36  35.194.45.10  n1-standard-1  1.14.10-gke.36  3          RUNNING
cluster-1  us-east1       1.14.10-gke.36  34.75.147.33  n1-standard-1  1.14.10-gke.36  9          RUNNING
</code></pre>
<p>You could also consider <code>gcloud container describe &lt;cluster-name&gt;</code> but you will need also specify if cluster is <code>regional</code> or <code>zonal</code> which it might be more like confirmation if it is <code>regional</code> or <code>zonal</code> cluster.</p>
