diff --git a/x-pack/plugin/inference/src/main/java/org/elasticsearch/xpack/inference/chunking/SentenceBoundaryChunker.java b/x-pack/plugin/inference/src/main/java/org/elasticsearch/xpack/inference/chunking/SentenceBoundaryChunker.java
index bc72a31d1e8b8..2e3a0667bb13b 100644
--- a/x-pack/plugin/inference/src/main/java/org/elasticsearch/xpack/inference/chunking/SentenceBoundaryChunker.java
+++ b/x-pack/plugin/inference/src/main/java/org/elasticsearch/xpack/inference/chunking/SentenceBoundaryChunker.java
@@ -158,6 +158,11 @@ public List<String> chunk(String input, int maxNumberWordsPerChunk, boolean incl
             chunks.add(input.substring(chunkStart));
         }
 
+        if (chunks.isEmpty()) {
+            // The input did not chunk, return the entire input
+            chunks.add(input);
+        }
+
         return chunks;
     }
 
diff --git a/x-pack/plugin/inference/src/test/java/org/elasticsearch/xpack/inference/chunking/EmbeddingRequestChunkerTests.java b/x-pack/plugin/inference/src/test/java/org/elasticsearch/xpack/inference/chunking/EmbeddingRequestChunkerTests.java
index 6b2a53de306aa..760882fa2b39d 100644
--- a/x-pack/plugin/inference/src/test/java/org/elasticsearch/xpack/inference/chunking/EmbeddingRequestChunkerTests.java
+++ b/x-pack/plugin/inference/src/test/java/org/elasticsearch/xpack/inference/chunking/EmbeddingRequestChunkerTests.java
@@ -45,6 +45,15 @@ public void testEmptyInput_SentenceChunker() {
         assertThat(batches, empty());
     }
 
+    public void testWhitespaceInput_SentenceChunker() {
+        var embeddingType = randomFrom(EmbeddingRequestChunker.EmbeddingType.values());
+        var batches = new EmbeddingRequestChunker(List.of("   "), 10, embeddingType, new SentenceBoundaryChunkingSettings(250, 1))
+            .batchRequestsWithListeners(testListener());
+        assertThat(batches, hasSize(1));
+        assertThat(batches.get(0).batch().inputs(), hasSize(1));
+        assertThat(batches.get(0).batch().inputs().get(0), Matchers.is("   "));
+    }
+
     public void testBlankInput_WordChunker() {
         var embeddingType = randomFrom(EmbeddingRequestChunker.EmbeddingType.values());
         var batches = new EmbeddingRequestChunker(List.of(""), 100, 100, 10, embeddingType).batchRequestsWithListeners(testListener());
@@ -62,6 +71,25 @@ public void testBlankInput_SentenceChunker() {
         assertThat(batches.get(0).batch().inputs().get(0), Matchers.is(""));
     }
 
+    public void testInputThatDoesNotChunk_WordChunker() {
+        var embeddingType = randomFrom(EmbeddingRequestChunker.EmbeddingType.values());
+        var batches = new EmbeddingRequestChunker(List.of("ABBAABBA"), 100, 100, 10, embeddingType).batchRequestsWithListeners(
+            testListener()
+        );
+        assertThat(batches, hasSize(1));
+        assertThat(batches.get(0).batch().inputs(), hasSize(1));
+        assertThat(batches.get(0).batch().inputs().get(0), Matchers.is("ABBAABBA"));
+    }
+
+    public void testInputThatDoesNotChunk_SentenceChunker() {
+        var embeddingType = randomFrom(EmbeddingRequestChunker.EmbeddingType.values());
+        var batches = new EmbeddingRequestChunker(List.of("ABBAABBA"), 10, embeddingType, new SentenceBoundaryChunkingSettings(250, 1))
+            .batchRequestsWithListeners(testListener());
+        assertThat(batches, hasSize(1));
+        assertThat(batches.get(0).batch().inputs(), hasSize(1));
+        assertThat(batches.get(0).batch().inputs().get(0), Matchers.is("ABBAABBA"));
+    }
+
     public void testShortInputsAreSingleBatch() {
         String input = "one chunk";
         var embeddingType = randomFrom(EmbeddingRequestChunker.EmbeddingType.values());
diff --git a/x-pack/plugin/inference/src/test/java/org/elasticsearch/xpack/inference/chunking/SentenceBoundaryChunkerTests.java b/x-pack/plugin/inference/src/test/java/org/elasticsearch/xpack/inference/chunking/SentenceBoundaryChunkerTests.java
index 5a350439ceffc..e8b3f09b11750 100644
--- a/x-pack/plugin/inference/src/test/java/org/elasticsearch/xpack/inference/chunking/SentenceBoundaryChunkerTests.java
+++ b/x-pack/plugin/inference/src/test/java/org/elasticsearch/xpack/inference/chunking/SentenceBoundaryChunkerTests.java
@@ -33,6 +33,35 @@ public void testEmptyString() {
         assertThat(chunks.get(0), Matchers.is(""));
     }
 
+    public void testBlankString() {
+        var chunks = new SentenceBoundaryChunker().chunk("   ", 100, randomBoolean());
+        assertThat(chunks, hasSize(1));
+        assertThat(chunks.get(0), Matchers.is("   "));
+    }
+
+    public void testSingleChar() {
+        var chunks = new SentenceBoundaryChunker().chunk("   b", 100, randomBoolean());
+        assertThat(chunks, Matchers.contains("   b"));
+
+        chunks = new SentenceBoundaryChunker().chunk("b", 100, randomBoolean());
+        assertThat(chunks, Matchers.contains("b"));
+
+        chunks = new SentenceBoundaryChunker().chunk(". ", 100, randomBoolean());
+        assertThat(chunks, Matchers.contains(". "));
+
+        chunks = new SentenceBoundaryChunker().chunk(" , ", 100, randomBoolean());
+        assertThat(chunks, Matchers.contains(" , "));
+
+        chunks = new SentenceBoundaryChunker().chunk(" ,", 100, randomBoolean());
+        assertThat(chunks, Matchers.contains(" ,"));
+    }
+
+    public void testSingleCharRepeated() {
+        var input = "a".repeat(32_000);
+        var chunks = new SentenceBoundaryChunker().chunk(input, 100, randomBoolean());
+        assertThat(chunks, Matchers.contains(input));
+    }
+
     public void testChunkSplitLargeChunkSizes() {
         for (int maxWordsPerChunk : new int[] { 100, 200 }) {
             var chunker = new SentenceBoundaryChunker();
diff --git a/x-pack/plugin/inference/src/test/java/org/elasticsearch/xpack/inference/chunking/WordBoundaryChunkerTests.java b/x-pack/plugin/inference/src/test/java/org/elasticsearch/xpack/inference/chunking/WordBoundaryChunkerTests.java
index ef643a4b36fdc..795f90aa29b02 100644
--- a/x-pack/plugin/inference/src/test/java/org/elasticsearch/xpack/inference/chunking/WordBoundaryChunkerTests.java
+++ b/x-pack/plugin/inference/src/test/java/org/elasticsearch/xpack/inference/chunking/WordBoundaryChunkerTests.java
@@ -11,6 +11,7 @@
 
 import org.elasticsearch.inference.ChunkingSettings;
 import org.elasticsearch.test.ESTestCase;
+import org.hamcrest.Matchers;
 
 import java.util.List;
 import java.util.Locale;
@@ -226,6 +227,35 @@ public void testWhitespace() {
         assertThat(chunks, contains(" "));
     }
 
+    public void testBlankString() {
+        var chunks = new WordBoundaryChunker().chunk("   ", 100, 10);
+        assertThat(chunks, hasSize(1));
+        assertThat(chunks.get(0), Matchers.is("   "));
+    }
+
+    public void testSingleChar() {
+        var chunks = new WordBoundaryChunker().chunk("   b", 100, 10);
+        assertThat(chunks, Matchers.contains("   b"));
+
+        chunks = new WordBoundaryChunker().chunk("b", 100, 10);
+        assertThat(chunks, Matchers.contains("b"));
+
+        chunks = new WordBoundaryChunker().chunk(". ", 100, 10);
+        assertThat(chunks, Matchers.contains(". "));
+
+        chunks = new WordBoundaryChunker().chunk(" , ", 100, 10);
+        assertThat(chunks, Matchers.contains(" , "));
+
+        chunks = new WordBoundaryChunker().chunk(" ,", 100, 10);
+        assertThat(chunks, Matchers.contains(" ,"));
+    }
+
+    public void testSingleCharRepeated() {
+        var input = "a".repeat(32_000);
+        var chunks = new WordBoundaryChunker().chunk(input, 100, 10);
+        assertThat(chunks, Matchers.contains(input));
+    }
+
     public void testPunctuation() {
         int chunkSize = 1;
         var chunks = new WordBoundaryChunker().chunk("Comma, separated", chunkSize, 0);