my $data = "00:01:00Something here bla bla blaTYPE00:02:00".
           "Something here bla bla blaANOTHERTYPE00:03:00S".
           "omething here bla bla blaEVENMORETYPES";

use Benchmark;

timethese (100000,

{ 
  withsplit => sub {
        my @lines = split /(?=\d\d:\d\d:\d\d)/, $data;
                   },

  nosplit   => sub {
        my @lines = $data =~ /(\d{2}:\d{2}:\d{2}[^\d]*)/g;
                   }
}

);