diff --git a/modules/nf-core/custom/clustermetrics/main.nf b/modules/nf-core/custom/clustermetrics/main.nf
index 2eb096b08f40..1ec2bc9c0c97 100644
--- a/modules/nf-core/custom/clustermetrics/main.nf
+++ b/modules/nf-core/custom/clustermetrics/main.nf
@@ -33,6 +33,7 @@ process CUSTOM_CLUSTERMETRICS {
     touch ${prefix}.silhouette.png
     touch ${prefix}.davies_bouldin.png
     touch ${prefix}.calinski_harabasz.png
+    touch ${prefix}.k_distance.png
 
     cat <<-END_VERSIONS > versions.yml
     "${task.process}":
diff --git a/modules/nf-core/custom/clustermetrics/meta.yml b/modules/nf-core/custom/clustermetrics/meta.yml
index e364f55b6f75..9e0272f7d346 100644
--- a/modules/nf-core/custom/clustermetrics/meta.yml
+++ b/modules/nf-core/custom/clustermetrics/meta.yml
@@ -1,12 +1,13 @@
 name: "CUSTOM_CLUSTERMETRICS"
 description: "Computes clustering quality metrics (silhouette, Calinski-Harabasz,
-  Davies-Bouldin) and performs k-sweep analysis"
+  Davies-Bouldin), performs k-sweep and k-distance analysis"
 keywords:
   - clustering
   - metrics
   - silhouette
   - calinski-harabasz
   - davies-bouldin
+  - k-distance
   - evaluation
 tools:
   - "scikit-learn":
@@ -25,9 +26,11 @@ input:
     - features:
         type: file
         description: |
-          Tab-separated feature matrix with a `sample_id` column and one
-          column per numeric feature (e.g. PCA scores).
-        pattern: "*.tsv"
+          Sample-by-feature matrix: TSV with a `sample_id` column, or a
+          PLINK2 `.eigenvec` file (`#FID IID PC1 ...` or `#IID PC1 ...`).
+          Family/source ID columns are dropped; remaining columns are
+          numeric features (e.g. PCA scores).
+        pattern: "*.{tsv,txt,eigenvec}"
         ontologies:
           - edam: http://edamontology.org/format_3475
     - clusters:
diff --git a/modules/nf-core/custom/clustermetrics/templates/cluster_metrics.py b/modules/nf-core/custom/clustermetrics/templates/cluster_metrics.py
index fd8856fd41cf..6a19d786d0b5 100644
--- a/modules/nf-core/custom/clustermetrics/templates/cluster_metrics.py
+++ b/modules/nf-core/custom/clustermetrics/templates/cluster_metrics.py
@@ -13,6 +13,7 @@
 
 matplotlib.use("Agg")
 import matplotlib.pyplot as plt
+import numpy as np
 import pandas as pd
 import sklearn
 import yaml
@@ -22,13 +23,28 @@
     davies_bouldin_score,
     silhouette_score,
 )
+from sklearn.neighbors import NearestNeighbors
 
 
 def load_features(path):
-    """Read a TSV of `sample_id` + numeric feature columns, indexed by sample_id."""
-    df = pd.read_csv(path, sep="\\t")
+    """Read sample-by-feature matrix, indexed by sample_id.
+
+    Accepts a TSV with a sample_id column, or a PLINK2 .eigenvec file
+    (`#FID IID PC1 ...` or `#IID PC1 ...`). FID/SID are dropped.
+    """
+    df = pd.read_csv(path, sep="\\t", dtype=str)
+    df.columns = [str(col).lstrip("#") for col in df.columns]
+
+    if "IID" in df.columns:
+        df = df.rename(columns={"IID": "sample_id"})
+
+    drop = [col for col in ("FID", "SID") if col in df.columns]
+    if drop:
+        df = df.drop(columns=drop)
+
     if "sample_id" not in df.columns:
         raise ValueError(f"features file must have a 'sample_id' column. Found: {list(df.columns)}")
+
     df["sample_id"] = df["sample_id"].astype(str)
     return df.set_index("sample_id").apply(pd.to_numeric, errors="coerce").fillna(0.0)
 
@@ -73,6 +89,28 @@ def plot_curve(sweep_df, metric, title, ylabel, out_png):
     plt.close()
 
 
+def plot_k_distance(x, k, out_png, eps=None):
+    """k-distance plot used to choose DBSCAN eps."""
+    k = int(min(max(k, 1), len(x) - 1))
+    nn = NearestNeighbors(n_neighbors=k + 1)
+    nn.fit(x)
+    distances, _ = nn.kneighbors(x)
+    k_distances = np.sort(distances[:, -1])
+
+    plt.figure(figsize=(8, 4))
+    plt.plot(k_distances)
+    if eps is not None:
+        plt.axhline(y=eps, linestyle="--", label=f"eps = {eps}")
+        plt.legend()
+    plt.ylabel(f"Distance to {k}-th nearest neighbour")
+    plt.xlabel("Points sorted by distance")
+    plt.title("k-distance plot")
+    plt.grid(True)
+    plt.tight_layout()
+    plt.savefig(out_png, dpi=200)
+    plt.close()
+
+
 def main():
     features = "$features"
     clusters_path = "$clusters"
@@ -83,6 +121,8 @@ def main():
     parser = argparse.ArgumentParser()
     parser.add_argument("--k-min", type=int, default=2)
     parser.add_argument("--k-max", type=int, default=12)
+    parser.add_argument("--k-neighbors", type=int, default=None)
+    parser.add_argument("--eps", type=float, default=None)
     opts = parser.parse_args(shlex.split(raw_args) if raw_args and raw_args != "null" else [])
 
     joined = load_features(features).join(load_clusters(clusters_path), how="inner")
@@ -127,6 +167,9 @@ def main():
             f"{prefix}.calinski_harabasz.png",
         )
 
+    k_neighbors = opts.k_neighbors if opts.k_neighbors is not None else x.shape[1]
+    plot_k_distance(x, k_neighbors, f"{prefix}.k_distance.png", eps=opts.eps)
+
     versions = {
         "${task.process}": {
             "python": platform.python_version(),
diff --git a/modules/nf-core/custom/clustermetrics/tests/main.nf.test b/modules/nf-core/custom/clustermetrics/tests/main.nf.test
index d5a42e682198..8b951c7e1cfe 100644
--- a/modules/nf-core/custom/clustermetrics/tests/main.nf.test
+++ b/modules/nf-core/custom/clustermetrics/tests/main.nf.test
@@ -37,6 +37,34 @@ nextflow_process {
         }
     }
 
+    test("clustermetrics - features from eigenvec") {
+
+        when {
+            process {
+                """
+                input[0] = [
+                    [ id:'test' ],
+                    file(params.modules_testdata_base_path + "genomics/homo_sapiens/popgen/clustering/test.eigenvec", checkIfExists: true),
+                    file(params.modules_testdata_base_path + "genomics/homo_sapiens/popgen/clustering/test_clusters.csv", checkIfExists: true)
+                ]
+                """
+            }
+        }
+
+        then {
+            assertAll(
+                { assert process.success },
+                { assert snapshot(
+                    process.out.metrics,
+                    process.out.k_sweep,
+                    process.out.selected,
+                    process.out.versions,
+                    path(process.out.versions[0]).yaml
+                ).match() }
+            )
+        }
+    }
+
     test("clustermetrics - features and clusters - stub") {
 
         options "-stub"
diff --git a/modules/nf-core/custom/clustermetrics/tests/main.nf.test.snap b/modules/nf-core/custom/clustermetrics/tests/main.nf.test.snap
index 0ec0df908bc5..6bdff3a47c01 100644
--- a/modules/nf-core/custom/clustermetrics/tests/main.nf.test.snap
+++ b/modules/nf-core/custom/clustermetrics/tests/main.nf.test.snap
@@ -78,6 +78,7 @@
                         "test.calinski_harabasz.png:md5,d41d8cd98f00b204e9800998ecf8427e",
                         "test.davies_bouldin.png:md5,d41d8cd98f00b204e9800998ecf8427e",
                         "test.elbow.png:md5,d41d8cd98f00b204e9800998ecf8427e",
+                        "test.k_distance.png:md5,d41d8cd98f00b204e9800998ecf8427e",
                         "test.silhouette.png:md5,d41d8cd98f00b204e9800998ecf8427e"
                     ]
                 ]
@@ -95,10 +96,54 @@
                 }
             }
         ],
-        "timestamp": "2026-05-19T14:11:36.600888057",
+        "timestamp": "2026-09-08T11:43:04.630166242",
         "meta": {
             "nf-test": "0.9.5",
-            "nextflow": "25.09.0"
+            "nextflow": "26.04.6"
+        }
+    },
+    "clustermetrics - features from eigenvec": {
+        "content": [
+            [
+                [
+                    {
+                        "id": "test"
+                    },
+                    "test.metrics.tsv:md5,15c36eab43e480e0311c4bcc3d511477"
+                ]
+            ],
+            [
+                [
+                    {
+                        "id": "test"
+                    },
+                    "test.k_sweep.csv:md5,98635ea739c5e136ced833916ae5d931"
+                ]
+            ],
+            [
+                [
+                    {
+                        "id": "test"
+                    },
+                    "test.selected.json:md5,d1d1b3788b7a111f38bf3b27d4bb1ab4"
+                ]
+            ],
+            [
+                "versions.yml:md5,602aa5dfe6c0b807d758c4f5cf3fc5e4"
+            ],
+            {
+                "CUSTOM_CLUSTERMETRICS": {
+                    "python": "3.12.13",
+                    "pandas": "3.0.3",
+                    "scikit-learn": "1.8.0",
+                    "matplotlib": "3.10.9"
+                }
+            }
+        ],
+        "timestamp": "2026-09-08T15:41:30.682155747",
+        "meta": {
+            "nf-test": "0.9.5",
+            "nextflow": "26.04.6"
         }
     }
 }
\ No newline at end of file
diff --git a/modules/nf-core/custom/clustervisualization/meta.yml b/modules/nf-core/custom/clustervisualization/meta.yml
index 62bed07814e5..7f3abf907165 100644
--- a/modules/nf-core/custom/clustervisualization/meta.yml
+++ b/modules/nf-core/custom/clustervisualization/meta.yml
@@ -29,9 +29,11 @@ input:
     - features:
         type: file
         description: |
-          Tab-separated feature matrix with a `sample_id` column and one
-          column per numeric feature (e.g. PCA scores).
-        pattern: "*.tsv"
+          Sample-by-feature matrix: TSV with a `sample_id` column, or a
+          PLINK2 `.eigenvec` file (`#FID IID PC1 ...` or `#IID PC1 ...`).
+          Family/source ID columns are dropped; remaining columns are
+          numeric features (e.g. PCA scores).
+        pattern: "*.{tsv,txt,eigenvec}"
         ontologies:
           - edam: http://edamontology.org/format_3475
     - clusters:
diff --git a/modules/nf-core/custom/clustervisualization/templates/cluster_viz.py b/modules/nf-core/custom/clustervisualization/templates/cluster_viz.py
index 6f6a60d5ac37..a46e4676ee11 100644
--- a/modules/nf-core/custom/clustervisualization/templates/cluster_viz.py
+++ b/modules/nf-core/custom/clustervisualization/templates/cluster_viz.py
@@ -29,10 +29,24 @@
 
 
 def load_features(path):
-    """Read a TSV of `sample_id` + numeric feature columns, indexed by sample_id."""
-    df = pd.read_csv(path, sep="\\t")
+    """Read sample-by-feature matrix, indexed by sample_id.
+
+    Accepts a TSV with a sample_id column, or a PLINK2 .eigenvec file
+    (`#FID IID PC1 ...` or `#IID PC1 ...`). FID/SID are dropped.
+    """
+    df = pd.read_csv(path, sep="\\t", dtype=str)
+    df.columns = [str(col).lstrip("#") for col in df.columns]
+
+    if "IID" in df.columns:
+        df = df.rename(columns={"IID": "sample_id"})
+
+    drop = [col for col in ("FID", "SID") if col in df.columns]
+    if drop:
+        df = df.drop(columns=drop)
+
     if "sample_id" not in df.columns:
         raise ValueError(f"features file must have a 'sample_id' column. Found: {list(df.columns)}")
+
     df["sample_id"] = df["sample_id"].astype(str)
     return df.set_index("sample_id").apply(pd.to_numeric, errors="coerce").fillna(0.0)
 
@@ -54,9 +68,9 @@ def embed(x, method, umap_neighbors, tsne_perplexity):
     """
     n = len(x)
     if method == "umap":
-        reducer = umap.UMAP(n_components=2, n_neighbors=min(umap_neighbors, max(2, n - 1)), random_state=42)
+        reducer = umap.UMAP(n_components=2, n_neighbors=min(umap_neighbors, max(2, n - 1)), n_jobs=1, random_state=42)
     elif method == "tsne":
-        reducer = TSNE(n_components=2, perplexity=min(tsne_perplexity, max(2, n - 1)), random_state=42)
+        reducer = TSNE(n_components=2, perplexity=min(tsne_perplexity, max(2, n - 1)), n_jobs=1, random_state=42)
     else:
         raise ValueError(f"Unknown method '{method}' (expected 'umap' or 'tsne')")
     return reducer.fit_transform(x)
diff --git a/modules/nf-core/custom/clustervisualization/tests/main.nf.test b/modules/nf-core/custom/clustervisualization/tests/main.nf.test
index 0334f0d09434..e33116c5ad7d 100644
--- a/modules/nf-core/custom/clustervisualization/tests/main.nf.test
+++ b/modules/nf-core/custom/clustervisualization/tests/main.nf.test
@@ -1,11 +1,14 @@
 nextflow_process {
+
     name "Test Process CUSTOM_CLUSTERVISUALIZATION"
     script "../main.nf"
     process "CUSTOM_CLUSTERVISUALIZATION"
+
     tag "modules"
     tag "modules_nfcore"
     tag "custom"
     tag "custom/clustervisualization"
+
     test("clustervisualization - features and clusters") {
         when {
             process {
@@ -18,18 +21,60 @@ nextflow_process {
                 """
             }
         }
+
         then {
+            def umap = path(process.out.umap_tsv[0][1]).csv(sep: "\t")
+            def tsne = path(process.out.tsne_tsv[0][1]).csv(sep: "\t")
             assertAll(
                 { assert process.success },
+                { assert umap.columnNames == ["sample_id", "Dim1", "Dim2", "cluster"] },
+                { assert tsne.columnNames == ["sample_id", "Dim1", "Dim2", "cluster"] },
+                { assert umap.rowCount == tsne.rowCount },
                 { assert snapshot(
-                    process.out.umap_tsv,
-                    process.out.tsne_tsv,
+                    umap.columnNames,
+                    umap.rowCount,
+                    tsne.columnNames,
+                    tsne.rowCount,
+                    process.out.versions,
+                    path(process.out.versions[0]).yaml
+                ).match() }
+            )
+        }
+    }
+
+    test("clustervisualization - features from eigenvec") {
+        when {
+            process {
+                """
+                input[0] = [
+                    [ id:'test' ],
+                    file(params.modules_testdata_base_path + "genomics/homo_sapiens/popgen/clustering/test.eigenvec", checkIfExists: true),
+                    file(params.modules_testdata_base_path + "genomics/homo_sapiens/popgen/clustering/test_clusters.csv", checkIfExists: true)
+                ]
+                """
+            }
+        }
+
+        then {
+            def umap = path(process.out.umap_tsv[0][1]).csv(sep: "\t")
+            def tsne = path(process.out.tsne_tsv[0][1]).csv(sep: "\t")
+            assertAll(
+                { assert process.success },
+                { assert umap.columnNames == ["sample_id", "Dim1", "Dim2", "cluster"] },
+                { assert tsne.columnNames == ["sample_id", "Dim1", "Dim2", "cluster"] },
+                { assert umap.rowCount == tsne.rowCount },
+                { assert snapshot(
+                    umap.columnNames,
+                    umap.rowCount,
+                    tsne.columnNames,
+                    tsne.rowCount,
                     process.out.versions,
                     path(process.out.versions[0]).yaml
                 ).match() }
             )
         }
     }
+
     test("clustervisualization - features and clusters - stub") {
         options "-stub"
         when {
@@ -43,6 +88,7 @@ nextflow_process {
                 """
             }
         }
+
         then {
             assertAll(
                 { assert process.success },
diff --git a/modules/nf-core/custom/clustervisualization/tests/main.nf.test.snap b/modules/nf-core/custom/clustervisualization/tests/main.nf.test.snap
index f180dfa8b993..3d113566219a 100644
--- a/modules/nf-core/custom/clustervisualization/tests/main.nf.test.snap
+++ b/modules/nf-core/custom/clustervisualization/tests/main.nf.test.snap
@@ -54,24 +54,58 @@
             "nextflow": "25.09.0"
         }
     },
+    "clustervisualization - features from eigenvec": {
+        "content": [
+            [
+                "sample_id",
+                "Dim1",
+                "Dim2",
+                "cluster"
+            ],
+            200,
+            [
+                "sample_id",
+                "Dim1",
+                "Dim2",
+                "cluster"
+            ],
+            200,
+            [
+                "versions.yml:md5,a00bfbb9b1b4145177ec0e8a7406caf9"
+            ],
+            {
+                "CUSTOM_CLUSTERVISUALIZATION": {
+                    "python": "3.12.13",
+                    "pandas": "3.0.3",
+                    "matplotlib": "3.10.9",
+                    "seaborn": "0.13.2",
+                    "umap-learn": "0.5.12",
+                    "scikit-learn": "1.8.0"
+                }
+            }
+        ],
+        "timestamp": "2026-09-08T15:44:25.637933809",
+        "meta": {
+            "nf-test": "0.9.5",
+            "nextflow": "26.04.6"
+        }
+    },
     "clustervisualization - features and clusters": {
         "content": [
             [
-                [
-                    {
-                        "id": "test"
-                    },
-                    "test.umap.tsv:md5,d338c1ef0e979dbf653e21c3417e975e"
-                ]
+                "sample_id",
+                "Dim1",
+                "Dim2",
+                "cluster"
             ],
+            200,
             [
-                [
-                    {
-                        "id": "test"
-                    },
-                    "test.tsne.tsv:md5,eb00f27d82530f665552b158e8e3c8ff"
-                ]
+                "sample_id",
+                "Dim1",
+                "Dim2",
+                "cluster"
             ],
+            200,
             [
                 "versions.yml:md5,a00bfbb9b1b4145177ec0e8a7406caf9"
             ],
@@ -86,10 +120,10 @@
                 }
             }
         ],
-        "timestamp": "2026-05-19T17:08:32.73077357",
+        "timestamp": "2026-09-08T12:55:48.907052107",
         "meta": {
             "nf-test": "0.9.5",
-            "nextflow": "25.10.2"
+            "nextflow": "26.04.6"
         }
     }
 }
\ No newline at end of file