diff --git a/src/sentence.rs b/src/sentence.rs
index 78d87b4..b4f367c 100644
--- a/src/sentence.rs
+++ b/src/sentence.rs
@@ -366,6 +366,11 @@ impl<'a> Iterator for UnicodeSentences<'a> {
     fn next(&mut self) -> Option<&'a str> {
         self.inner.next()
     }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.inner.size_hint()
+    }
 }
 
 impl<'a> Iterator for USentenceBounds<'a> {
diff --git a/src/word.rs b/src/word.rs
index 16dfafd..0ee9d59 100644
--- a/src/word.rs
+++ b/src/word.rs
@@ -36,6 +36,11 @@ impl<'a> Iterator for UnicodeWords<'a> {
     fn next(&mut self) -> Option<&'a str> {
         self.inner.next()
     }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.inner.size_hint()
+    }
 }
 impl<'a> DoubleEndedIterator for UnicodeWords<'a> {
     #[inline]
@@ -68,6 +73,11 @@ impl<'a> Iterator for UnicodeWordIndices<'a> {
     fn next(&mut self) -> Option<(usize, &'a str)> {
         self.inner.next()
     }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.inner.size_hint()
+    }
 }
 impl<'a> DoubleEndedIterator for UnicodeWordIndices<'a> {
     #[inline]