diff --git a/src/ipv6.rs b/src/ipv6.rs
index 916ec66..90503f1 100644
--- a/src/ipv6.rs
+++ b/src/ipv6.rs
@@ -1,3 +1,4 @@
+use std::cmp;
 use std::fmt;
 use std::net::Ipv6Addr;
 use std::str::FromStr;
@@ -41,6 +42,50 @@ impl Ipv6Network {
     pub fn prefix(&self) -> u8 {
         self.prefix
     }
+
+    /// Returns the mask for this `Ipv6Network`.
+    /// That means the `prefix` most significant bits will be 1 and the rest 0
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::net::Ipv6Addr;
+    /// use ipnetwork::Ipv6Network;
+    ///
+    /// let net = Ipv6Network::from_cidr("ff01::0/32").unwrap();
+    /// assert_eq!(net.mask(), Ipv6Addr::new(0xffff, 0xffff, 0, 0, 0, 0, 0, 0));
+    /// ```
+    pub fn mask(&self) -> Ipv6Addr {
+        // Ipv6Addr::from is only implemented for [u8; 16]
+        let mut segments = [0; 16];
+        for (i, segment) in segments.iter_mut().enumerate() {
+            let bits_remaining = self.prefix.saturating_sub(i as u8 * 8);
+            let set_bits = cmp::min(bits_remaining, 8);
+            *segment = !(0xff as u16 >> set_bits) as u8;
+        }
+        Ipv6Addr::from(segments)
+    }
+
+    /// Checks if a given `Ipv6Addr` is in this `Ipv6Network`
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::net::Ipv6Addr;
+    /// use ipnetwork::Ipv6Network;
+    ///
+    /// let net = Ipv6Network::from_cidr("ff01::0/32").unwrap();
+    /// assert!(net.contains(Ipv6Addr::new(0xff01, 0, 0, 0, 0, 0, 0, 0x1)));
+    /// assert!(!net.contains(Ipv6Addr::new(0xffff, 0, 0, 0, 0, 0, 0, 0x1)));
+    /// ```
+    pub fn contains(&self, ip: Ipv6Addr) -> bool {
+        let a = self.addr.segments();
+        let b = ip.segments();
+        let addrs = Iterator::zip(a.iter(), b.iter());
+        self.mask().segments().iter().zip(addrs).all(|(mask, (a, b))|
+            a & mask == b & mask
+        )
+    }
 }
 
 impl fmt::Display for Ipv6Network {
@@ -92,4 +137,25 @@ mod test {
         let cidr = Ipv6Network::from_cidr("::1/129");
         assert!(cidr.is_err());
     }
+
+    #[test]
+    fn mask_v6() {
+        let cidr = Ipv6Network::new(Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 0), 40).unwrap();
+        let mask = cidr.mask();
+        assert_eq!(mask, Ipv6Addr::new(0xffff, 0xffff, 0xff00, 0, 0, 0, 0, 0));
+    }
+
+    #[test]
+    fn contains_v6() {
+        let cidr = Ipv6Network::new(Ipv6Addr::new(0xff01, 0, 0, 0x17, 0, 0, 0, 0x2), 65).unwrap();
+        let ip = Ipv6Addr::new(0xff01, 0, 0, 0x17, 0x7fff, 0, 0, 0x2);
+        assert!(cidr.contains(ip));
+    }
+
+    #[test]
+    fn not_contains_v6() {
+        let cidr = Ipv6Network::new(Ipv6Addr::new(0xff01, 0, 0, 0x17, 0, 0, 0, 0x2), 65).unwrap();
+        let ip = Ipv6Addr::new(0xff01, 0, 0, 0x17, 0xffff, 0, 0, 0x2);
+        assert!(!cidr.contains(ip));
+    }
 }